BUG: Initializes CMAKE_DEBUG_POSTFIX to be empty
BUG: Initializes CMAKE_DEBUG_POSTFIX to be empty

When GoogleTest third party module was updated (commit 5be14a56),
CMAKE_DEBUG_POSTFIX was set to 'd', which means that the ITK library
filenames will end with 'd'. This is not how ITK libraries used to
be named. To keep backward compatibility, we remove this postfix.

Change-Id: I802dcff5c6210692d64c38668b59c19c3c823662

hjmjohnson/ITK,LucasGandel/ITK,spinicist/ITK,BRAINSia/ITK,blowekamp/ITK,richardbeare/ITK,blowekamp/ITK,spinicist/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,spinicist/ITK,richardbeare/ITK,BRAINSia/ITK,stnava/ITK,Kitware/ITK,spinicist/ITK,fbudin69500/ITK,thewtex/ITK,malaterre/ITK,malaterre/ITK,malaterre/ITK,thewtex/ITK,Kitware/ITK,blowekamp/ITK,stnava/ITK,InsightSoftwareConsortium/ITK,vfonov/ITK,hjmjohnson/ITK,stnava/ITK,richardbeare/ITK,BRAINSia/ITK,blowekamp/ITK,LucasGandel/ITK,spinicist/ITK,fbudin69500/ITK,blowekamp/ITK,spinicist/ITK,vfonov/ITK,stnava/ITK,InsightSoftwareConsortium/ITK,fbudin69500/ITK,fbudin69500/ITK,thewtex/ITK,stnava/ITK,BRAINSia/ITK,LucasGandel/ITK,thewtex/ITK,LucasGandel/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,Kitware/ITK,blowekamp/ITK,vfonov/ITK,vfonov/ITK,malaterre/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,blowekamp/ITK,hjmjohnson/ITK,richardbeare/ITK,stnava/ITK,BRAINSia/ITK,stnava/ITK,thewtex/ITK,malaterre/ITK,malaterre/ITK,spinicist/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,malaterre/ITK,Kitware/ITK,BRAINSia/ITK,fbudin69500/ITK,hjmjohnson/ITK,vfonov/ITK,LucasGandel/ITK,hjmjohnson/ITK,vfonov/ITK,fbudin69500/ITK,vfonov/ITK,spinicist/ITK,thewtex/ITK,fbudin69500/ITK,blowekamp/ITK,BRAINSia/ITK,richardbeare/ITK,malaterre/ITK,hjmjohnson/ITK,Kitware/ITK,spinicist/ITK,stnava/ITK,richardbeare/ITK,richardbeare/ITK,vfonov/ITK,malaterre/ITK,fbudin69500/ITK,Kitware/ITK,vfonov/ITK,stnava/ITK,thewtex/ITK