xl: free pid string in do_daemonize

Pid is a null terminated string allocated by asprintf. It should be
freed after use.

Also fixed a coding style problem while I was there.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxl/xl_cmdimpl.c

@@ -524,10 +524,12 @@ static int do_daemonize(char *name, const char *pidfile)
             exit(1);
         }
 
-        if ( close(fd) < 0 ) {
+        if (close(fd) < 0) {
             perror("Closing pidfile");
             exit(1);
         }
+
+        free(pid);
     }
 
 out: