buffer: Use GL_STREAM_DRAW on GLES2
buffer: Use GL_STREAM_DRAW on GLES2

The function to convert the CoglBufferUpdateHint to a GL enum was
previously ifdef'd to only use GL_STREAM_DRAW when Cogl is compiled
with big GL support. One problem with this is that it would end up
trying to use it on GLES1 if support for both is compiled. The other
problem is that GLES2 seems to actually support GL_STREAM_DRAW so we
might as well use it in that case.

This patch also changes it so that if the hint is stream with GLES1
then it will default to GL_DYNAMIC_DRAW instead of GL_STATIC_DRAW
because I think that is closer to the meaning of the stream hint.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 9e997476a7f9271bc000abdc82b1e343b92afb4c)

Distrotech/cogl,Distrotech/cogl,Distrotech/cogl,Distrotech/cogl