svga: fix regression related to srgb
svga: fix regression related to srgb

This regression is caused because of commit 3190c7ee9727161d627f107c2e7f8ec3a11941c1
Regression caused by following OpenGL 4.4 spec rules relates to
GL_FRAMEBUFFER_SRGB in Mesa.

Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>
Reviewed-by: Charmaine Lee <67ce69700661ea856134ddb10419a330e5f037d7@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler