Fix memory leak created by hanging opendir

Change-Id: I01e372c6a6b427f21e89cb5e4217f876346a35be
Signed-off-by: Galantsev, Dmitrii <dmitrii.galantsev@amd.com>

rocm_smi/src/rocm_smi_utils.cc

@@ -503,6 +503,7 @@ std::vector<std::string> getListOfAppTmpFiles() {
       continue;
     }
   }
+  closedir(dir);
   return tmpFiles;
 }