COMP: Ensure executable are excluded from fixup process.

While GP_IS_FILE_EXECUTABLE_EXCLUDE_REGEX is convenient to speed-up the
function 'get_bundle_all_executables', when set if prevent file with '.exe'
extension from being excluded on non windows platform.

This commit will help fixing the following packaging error:

609 - fixing item /Users/kitware/Dashboards/Nightly/Slicer-build-64bits-QT4.8.5-PythonQt-With-Tcl-CLI-Release-nightly/Slicer-build/bin/libqSlicerApp.dylib with @rpath/lib/Slicer-4.3
install_name_tool: input file: /Users/kitware/Dashboards/Nightly/Slicer-build-64bits-QT4.8.5-PythonQt-With-Tcl-CLI-Release-nightly/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.3.1-2014-07-03-macosx-amd64/Slicer.app/Contents/lib/Python/lib/python2.7/site-packages/distribute-0.6.17-py2.7.egg/setuptools/cli.exe is not a Mach-O file
install_name_tool: input file: /Users/kitware/Dashboards/Nightly/Slicer-build-64bits-QT4.8.5-PythonQt-With-Tcl-CLI-Release-nightly/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.3.1-2014-07-03-macosx-amd64/Slicer.app/Contents/lib/Python/lib/python2.7/site-packages/distribute-0.6.17-py2.7.egg/setuptools/gui.exe is not a Mach-O file
CPack Error: Error when generating package: Slicer
make: *** [package] Error 1

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23419 3bd1e089-480b-0410-8dfb-8563597acbee