r.proj: fix https://trac.osgeo.org/grass/ticket/1262, r.proj was still crashing on Windows (merge from trunk, https://trac.osgeo.org/grass/changeset/61327)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@61328 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.proj/main.c

@@ -552,7 +552,7 @@ int main(int argc, char **argv)
     Rast_command_history(&history);
     Rast_write_history(mapname, &history);
 
-    G_done_msg(NULL);
+    G_done_msg(" ");
     exit(EXIT_SUCCESS);
 }