Silence two compiler warnings about redifinition of LOG, no bug

--HG--
extra : rebase_source : b2ad9b63ef071b71620506e78bcf12d507eb6577

uriloader/prefetch/OfflineCacheUpdateChild.cpp

@@ -44,6 +44,7 @@ using namespace mozilla::ipc;
 //
 extern PRLogModuleInfo *gOfflineCacheUpdateLog;
 #endif
+#undef LOG
 #define LOG(args) PR_LOG(gOfflineCacheUpdateLog, 4, args)
 #define LOG_ENABLED() PR_LOG_TEST(gOfflineCacheUpdateLog, 4)
 

uriloader/prefetch/nsOfflineCacheUpdateService.cpp

@@ -63,6 +63,7 @@ typedef mozilla::docshell::OfflineCacheUpdateGlue OfflineCacheUpdateGlue;
 //
 PRLogModuleInfo *gOfflineCacheUpdateLog;
 #endif
+#undef LOG
 #define LOG(args) PR_LOG(gOfflineCacheUpdateLog, 4, args)
 #define LOG_ENABLED() PR_LOG_TEST(gOfflineCacheUpdateLog, 4)