fix for STORM-1053: crash at LLTextureCache::writeToCache
fix for STORM-1053: crash at LLTextureCache::writeToCache

gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm,gabeharms/firestorm