Fix importer package install on 7.4

~/nuxeo-cap-7.4-tomcat ~
Detected Tomcat server.
Nuxeo home:          /Users/harlan/nuxeo-cap-7.4-tomcat
Nuxeo configuration: /Users/harlan/nuxeo-cap-7.4-tomcat/bin/nuxeo.conf
Include template: /Users/harlan/nuxeo-cap-7.4-tomcat/templates/common-base
Include template: /Users/harlan/nuxeo-cap-7.4-tomcat/templates/common
Include template: /Users/harlan/nuxeo-cap-7.4-tomcat/templates/default

Dependency resolution:
  Installation order (1):        nuxeo-platform-importer-1.6.3
  Packages to download (1):      nuxeo-platform-importer:1.6.3

Downloading [nuxeo-platform-importer-1.6.3]...
Added nuxeo-platform-importer-1.6.3
Installing nuxeo-platform-importer-1.6.3
Got warnings on package validation nuxeo-platform-importer-1.6.3 -> [Ignored command in installer. Source file not found! lib]
Can't update using /Users/harlan/nuxeo-cap-7.4-tomcat/packages/store/nuxeo-platform-importer-1.6.3/install/lib. File is missing.
~