[Development] Important OSX 10.9.5 & 10.10 codesign changes

[Sorvig Morten]

> 
> And the Info.plist should *always* set CFBundleExecutable to QtCore. To use the debug version you set the DYLD_IMAGE_SUFFIX environment variable to _debug prior to execution.

A minor case: What would you do for debug-only builds?

> 
> As far as I'm aware, we already do this correctly (aside from Info.plist being in the wrong place), and the only reason _debug is showing up in an Info.plist somewhere is probably due to some simple typo or omission.

Looks like it comes from the @EXECUTABLE@ -> var(“QMAKE_ORIG_TARGET”) substitution in unixmake2.cpp. 

I think the release build is racing the debug build, causing “_debug" to appear in some frameworks. So for a release+debug build we have two options:
1) Use the release Info.plist. (the current suggested approach)
2) Make sure they are identical.

Morten