Unable to use inside document content the velocity macros defined in skin templates

Steps to reproduce:
1. Define a variable and a macro in skins/flamingo/view.vm
2. Call that macro and variable in a document
3. The macro will not be visible, but the variable will be

Restarting the wiki does not help either, the macro defined in the template will just no be visible at all from a document.

The currently failing test for this is: http://ci.xwiki.org/job/xwiki-enterprise-test-selenium/lastBuild/org.xwiki.enterprise$xwiki-enterprise-test-selenium/testReport/org.xwiki.test.selenium/VelocityMacrosTest/testUsingMacroInGetRenderedContent/ (macro defined in a skin object's property)

Note that this test was added for fixing XWIKI-2340 (Macros declared before a call to $doc.getRenderedContent() in custom XWiki.XWikiSkins skin object are not taken into account).