build-sys: remove --enable-opengl
build-sys: remove --enable-opengl

OpenGL was removed in commit c5c176a5c7, enabling it on discheck will
fail to link with spice-common gl-enabled library

Signed-off-by: Marc-André Lureau <a6f2b960a4aca61381fc650a67901b2ac8e83e6d@gmail.com>

SPICE/spice,SPICE/spice,fgouget/spice,fgouget/spice,SPICE/spice,fgouget/spice,fgouget/spice