qemu-ga: Drop pointless lseek() from ga_open_pidfile()

After open(), the file offset is already zero, and neither lockf() nor
ftruncate() change it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

qga/main.c

@@ -289,7 +289,7 @@ static bool ga_open_pidfile(const char *pidfile)
         return false;
     }
 
-    if (ftruncate(pidfd, 0) || lseek(pidfd, 0, SEEK_SET)) {
+    if (ftruncate(pidfd, 0)) {
         g_critical("Failed to truncate pid file");
         goto fail;
     }