Fix parallelized build with modules relying on npm

mvn -DskipTests install -Paddons -T 1C

[INFO] --- maven-install-plugin:2.5.1:install (default-install) @ nuxeo-theme-webapp-compat ---
[INFO] Installing /home/anahide/ws/nuxeo-new/addons/nuxeo-theme-compat/nuxeo-theme-webapp-compat/target/nuxeo-theme-webapp-compat-8.4-SNAPSHOT.jar to 
/home/anahide/.m2/repository/org/nuxeo/theme/nuxeo-theme-webapp-compat/8.4-SNAPSHOT/nuxeo-theme-webapp-compat-8.4-SNAPSHOT.jar
[INFO] Installing /home/anahide/ws/nuxeo-new/addons/nuxeo-theme-compat/nuxeo-theme-webapp-compat/pom.xml to /home/anahide/.m2/repository/org/nuxeo/the
me/nuxeo-theme-webapp-compat/8.4-SNAPSHOT/nuxeo-theme-webapp-compat-8.4-SNAPSHOT.pom
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Nuxeo Forum Service API 8.4-SNAPSHOT
[INFO] ------------------------------------------------------------------------
     [exec] npm ERR! Linux 3.19.0-64-generic
     [exec] npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "cache" "clean"     [exec] npm ERR! tar.unpack error reading /home/anahide/.npm/is-utf8/0.2.1/package.tgz

     [exec] npm ERR! node v0.12.7
     [exec] npm ERR! npm  v2.11.3
     [exec] npm ERR! path /home/anahide/.npm/async-each-series/0.1.1/package
     [exec] npm ERR! code ENOTEMPTY
     [exec] npm ERR! errno -39
     [exec] 
     [exec] npm ERR! ENOTEMPTY, rmdir '/home/anahide/.npm/async-each-series/0.1.1/package'
     [exec] npm ERR! 
     [exec] npm ERR! If you need help, you may report this error at:
     [exec] npm ERR!     <https://github.com/npm/npm/issues>
     [exec] 
     [exec] npm ERR! Please include the following file with any support request:
     [exec] npm ERR!     /home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics/npm-debug.log
[INFO] 
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (default) @ nuxeo-platform-forum-api ---

[...]

[INFO] ------------------------------------------------------------------------
[INFO] Building Nuxeo Forum Service API 8.4-SNAPSHOT
[INFO] ------------------------------------------------------------------------
     [exec] npm ERR! Linux 3.19.0-64-generic
     [exec] npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "cache" "clean"     [exec] npm ERR! tar.unpack error reading /home/anahide/.npm/is-utf8/0.2.1/package.tgz

     [exec] npm ERR! node v0.12.7
     [exec] npm ERR! npm  v2.11.3
     [exec] npm ERR! path /home/anahide/.npm/async-each-series/0.1.1/package
     [exec] npm ERR! code ENOTEMPTY
     [exec] npm ERR! errno -39
     [exec] 
     [exec] npm ERR! ENOTEMPTY, rmdir '/home/anahide/.npm/async-each-series/0.1.1/package'
     [exec] npm ERR! 
     [exec] npm ERR! If you need help, you may report this error at:
     [exec] npm ERR!     <https://github.com/npm/npm/issues>
     [exec] 
     [exec] npm ERR! Please include the following file with any support request:
     [exec] npm ERR!     /home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics/npm-debug.log
[INFO] 
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (default) @ nuxeo-platform-forum-api ---

[...]

[INFO] ------------------------------------------------------------------------
     [exec] npm WARN deprecated minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
     [exec] npm ERR! tar.unpack error reading /home/anahide/.npm/multipipe/0.1.2/package.tgz
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:run (grunt-build) on project nuxeo-admin-center-analytics: An Ant BuildException has occured: The following error occurred while executing this line:
[ERROR] /home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics/build.xml:24: exec returned: 217
[ERROR] around Ant part ...<ant antfile="/home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics/build.xml" dir="/home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics"></ant>... @ 4:214 in /home/anahide/ws/nuxeo-new/nuxeo-features/nuxeo-admin-center/nuxeo-admin-center-analytics/target/antrun/build-main.xml
[ERROR] -> [Help 1]