util: virdaemon: fix waiting for child processes

Unlike `waitpid`, `virProcessWait` only returns -1 (error) or 0
(success), so comparing that to `pid` will always be false and the
parent will report failure with:

error : main:851 : Failed to fork as daemon: No such file or directory

even though the grandchild process is succesfully running. Note that the
errno message is misleading: it was last set when trying to find a
restart state file.
Signed-off-by: NRafael Fonseca <r4f4rfs@gmail.com>
Reported-by: NMarcin Krol <hawk@tld-linux.org>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>
(cherry-picked from commit a87e4788)
Signed-off-by: NXu Yandong <xuyandong2@huawei.com>

src/util/virdaemon.c

@@ -97,15 +97,14 @@ virDaemonForkIntoBackground(const char *argv0)
     default:
         {
             /* parent */
-            int got, exitstatus = 0;
+            int exitstatus = 0;
             int ret;
             char status;
 
             VIR_FORCE_CLOSE(statuspipe[1]);
 
             /* We wait to make sure the first child forked successfully */
-            if ((got = virProcessWait(pid, &exitstatus, 0)) < 0 ||
-                got != pid ||
+            if (virProcessWait(pid, &exitstatus, 0) < 0 ||
                 exitstatus != 0) {
                 goto error;
             }