pipeline: Fix argument checking in set_depth_state()
pipeline: Fix argument checking in set_depth_state()

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