gltrace: Change internalformat of some DSA routines to enum_ints.

Fix the tracing of glTextureImage?D and glMultiTexImage?DEXT routines
from the EXT_direct_state_access extension.  The type of the internalformat
argument is supposed to be GLint, not GLenum.  This can be confirmed here:

   http://www.opengl.org/registry/api/GL/glext.h

and here:

   http://www.opengl.org/registry/specs/EXT/direct_state_access.txt