Fix leak during discovery

Signed-off-by: falkTX <falktx@falktx.com>

source/discovery/carla-discovery.cpp

@@ -2684,6 +2684,7 @@ int main(int argc, const char* argv[])
     if (std::strcmp(filename, ":all") == 0)
     {
         do_cached_check(type);
+        gPipe = nullptr;
         return 0;
     }
    #endif