Fixed some warnings on GCC

Mozilla has recently made using NULL as integer an error (via
-Werror=conversion-null GCC flag), which caused ANGLE to no longer compile on
mingw in Mozilla tree. The ones that may not be obvious are removal of some <0
checks. They are not needed because they were done on unsigned types.

Author: Jacek Caban
http://codereview.appspot.com/6679049

(With changes to apply to dx11proto branch)

git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1464 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libGLESv2/ProgramBinary.cpp b/src/libGLESv2/ProgramBinary.cpp
index ed44c36..c0bcc6a 100644
--- a/src/libGLESv2/ProgramBinary.cpp
+++ b/src/libGLESv2/ProgramBinary.cpp
@@ -1046,7 +1046,7 @@
         return NULL;
     }
 
-    DWORD result = NOERROR;
+    HRESULT result = S_OK;
     UINT flags = 0;
     std::string sourceText;
     if (perfActive())