Fix GLIMP_LOGCOMMENT crashes

Author: slipher

src/engine/renderer/tr_shade.cpp

@@ -753,7 +753,7 @@ void Tess_Begin( void ( *stageIteratorFunc )(),
 
 	GLIMP_LOGCOMMENT( "--- Tess_Begin( surfaceShader = %s, "
 		"skipTangents = %i, lightmapNum = %i, fogNum = %i) ---",
-		tess.surfaceShader->name,
+		tess.surfaceShader ? tess.surfaceShader->name : "NULL",
 		tess.skipTangents, tess.lightmapNum, tess.fogNum );
 }
 

src/engine/renderer/tr_vbo.cpp

@@ -475,6 +475,8 @@ void R_BindVBO( VBO_t *vbo )
 		} else {
 			Sys::Drop( "R_BindNullVBO: NULL vbo" );
 		}
+
+		return;
 	}
 
 	GLIMP_LOGCOMMENT( "--- R_BindVBO( %s ) ---", vbo->name );