Modernize: use emplace instead of push_back

We had a couple uses of push_back in the code that could be made more
efficient with emplace().  Use them instead.

Tested: No functional change.  Needs tested.

Signed-off-by: Ed Tanous <ed.tanous@intel.com>
Change-Id: I417601e416b1d0be989617a372978d52670135d8
diff --git a/redfish-core/lib/account_service.hpp b/redfish-core/lib/account_service.hpp
index 7f34949..07efeb5 100644
--- a/redfish-core/lib/account_service.hpp
+++ b/redfish-core/lib/account_service.hpp
@@ -488,8 +488,8 @@
                                     }
                                 }
 
-                                confData.groupRoleList.push_back(std::make_pair(
-                                    object.first.str, roleMapData));
+                                confData.groupRoleList.emplace_back(
+                                    object.first.str, roleMapData);
                             }
                         }
                     }