src/useradd.c: set_defaults(): Fix FILE* leak

Report:
> shadow-4.15.0/src/useradd.c:575:2: alloc_fn: Storage is returned from allocation function "fdopen".
> shadow-4.15.0/src/useradd.c:575:2: var_assign: Assigning: "ofp" = storage returned from "fdopen(ofd, "w")".
> shadow-4.15.0/src/useradd.c:734:2: leaked_storage: Variable "ofp" going out of scope leaks the storage it points to.
> 732|           }
> 733|
> 734|->         return ret;
> 735|   }
> 736|

Link: <https://issues.redhat.com/browse/RHEL-35383>
Reported-by: Iker Pedrosa <ipedrosa@redhat.com>
Reviewed-by: Iker Pedrosa <ipedrosa@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

src/useradd.c

@@ -615,7 +615,8 @@ static int set_defaults (void)
 				fprintf (stderr,
 				         _("%s: line too long in %s: %s..."),
 				         Prog, default_file, buf);
-				(void) fclose (ifp);
+				fclose(ifp);
+				fclose(ofp);
 				goto err_free_def;
 			}
 		}