Revert "#229 - check for null before dispose messsage"

This reverts commit 6176e1b.

Author: Backs

Source/MSBuild.Community.Tasks/Mail.cs

@@ -292,10 +292,11 @@ public override bool Execute()
             }
             finally
             {
-	            message?.Dispose();
+                if(message == null)
+                    message.Dispose();
             }
-
-	        return true;
+            
+            return true;
         }
     }
 }