YARN-9711. Missing spaces in NMClientImpl (#1177) Contributed by Charles Xu.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/main/java/org/apache/hadoop/yarn/client/api/impl/NMClientImpl.java

@@ -130,11 +130,11 @@ public class NMClientImpl extends NMClient {
       } catch (YarnException e) {
         LOG.error("Failed to stop Container " +
             startedContainer.getContainerId() +
-            "when stopping NMClientImpl");
+            " when stopping NMClientImpl");
       } catch (IOException e) {
         LOG.error("Failed to stop Container " +
             startedContainer.getContainerId() +
-            "when stopping NMClientImpl");
+            " when stopping NMClientImpl");
       }
     }
   }