FIX: [droid] allow to build without debugging and pickup jenkins configuration

/cc @Memphiz @wsnipex @Montellese 
the actual issue is that you cannot set vars as a target dependency. Wasn't sure about it, but I just verified it. So neither what you have in the PR should work. Are 100% sure it does for you?

The way to do this is to run configure with the desired --enable-debug option for the release (and possibly a debug) target.