[Cogl] Remove a debugging assert that was triggering on false positives
[Cogl] Remove a debugging assert that was triggering on false positives

An assert to verify there was no error when generating a buffer object
for the vertex buffer API was being hit when running the GLES1 conformance
tests.

djdeath/cogl-android,gcampax/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,djdeath/cogl,collects/cogl,gcampax/cogl,djdeath/cogl-android,djdeath/cogl,Distrotech/cogl,gcampax/cogl,spatulasnout/cogl,collects/cogl,Distrotech/cogl,Distrotech/cogl,spatulasnout/cogl,djdeath/cogl-android