Merge pull request #1064 from mraghavan/coverity-22-07

coverity/71508: Fix potential null dereference.

src/nvim/os/provider.c

@@ -158,8 +158,10 @@ static uint64_t get_provider_for(char *method)
 
 err:
   // Ensure we won't try to restart the provider
+  if (f) {
     f->bootstrap_command = NULL;
     f->channel_id = 0;
+  }
   return 0;
 }