[MASSEMBLY-743] Cannot interpolate boolean values

Fixed with IT. Testcase supplied by Jean-Eric Cuendet.

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1644916 13f79535-47bb-0310-9956-ffa450edef68
OMG a missing space.

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1644955 13f79535-47bb-0310-9956-ffa450edef68