glamor: fixes GL_INVALID_ENUM errors on ES if there is no quads
If there is no quads to draw, then we have a possibility to call glDrawElements with count as zero, which will generate GL_INVALID_ENUM error. While this error is harmless, it is annoying.
Signed-off-by: Konstantin ria.freelander@gmail.com
Part of !924 (closed)
Edited by Konstantin