Fix infinite loop when using mp-set on 8.10

Steps to reproduce:

• On a new 8.10 run the following commands in any order:

  nuxeoctl --accept=true --relax=false --ignore-missing mp-set nuxeo-jsf-ui nuxeo-web-ui nuxeo-dam nuxeo-spreadsheet nuxeo-api-playground nuxeo-showcase-content nuxeo-template-rendering nuxeo-template-rendering-samples nuxeo-csv nuxeo-drive easyshare
  
  nuxeoctl mp-hotfix --accept=true
  

In both cases, it results in an infinite loop, installing and uninstalling the first HF.

Workaround: use mp-install instead of mp-set. This workaround seems to make sense if mp-hotfix was run first, but the problem still occurs when it is run after installing the other packages – there are just fewer HFs to uninstall before it enters the loop.