comutil changes for __uuidof support

Patched some whiteroom code that was previously compiled in MSVC to be
GNU GCC compatible.

git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@2436 4407c894-4637-0410-b4f5-ada5f102cad1
(cherry picked from commit 0d81bc40906a8cc0fd0b296bfaf5b2949e88616d)
comip.h: Don't use templates for functions that don't use its parameters.
(cherry picked from commit e712bb8b106d059914388e6ccd93c584a6416082)