Fix bug for array-formatted identities of user mappings

I failed to realize that server names reported in the object args array
would get quoted, which is wrong; remove that, making sure that it's
only quoted in the string-formatted identity.

This bug was introduced by my commit cf34e373, which was backpatched,
but since object name/args arrays are new in commit a6762014, there
is no need to backpatch this any further.

src/backend/catalog/objectaddress.c

@@ -4254,7 +4254,7 @@ getObjectIdentityParts(const ObjectAddress *object,
 				ReleaseSysCache(tup);
 
 				if (OidIsValid(useid))
-					usename = quote_identifier(GetUserNameFromId(useid));
+					usename = GetUserNameFromId(useid);
 				else
 					usename = "public";
 
@@ -4264,7 +4264,8 @@ getObjectIdentityParts(const ObjectAddress *object,
 					*objargs = list_make1(pstrdup(srv->servername));
 				}
 
-				appendStringInfo(&buffer, "%s on server %s", usename,
+				appendStringInfo(&buffer, "%s on server %s",
+								 quote_identifier(usename),
 								 srv->servername);
 				break;
 			}