Bug 1073036. Fix an assertion string that I forgot about.

--HG--
extra : rebase_source : 9c52d35673e7a28d2c982a070e28b18792cc1a98

gfx/layers/opengl/OGLShaderProgram.cpp

@@ -548,7 +548,7 @@ ShaderProgramOGL::GetProgram()
       NS_WARNING("Shader could not be initialised");
     }
   }
-  MOZ_ASSERT(HasInitialized(), "Attempting to activate a program that's not in use!");
+  MOZ_ASSERT(HasInitialized(), "Attempting to get a program that's not been initialized!");
   return mProgram;
 }