xl: fixes for do_daemonize

Fix usage of CHK_ERRNO in do_daemonize and also remove the usage of a
bogus for(;;).

Coverity-ID: 1130516 and 1130520
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit ed8c9047f6)

Conflicts:
	tools/libxl/xl_cmdimpl.c

tools/libxl/xl_cmdimpl.c

@@ -2079,14 +2079,14 @@ start:
         if (child1) {
             printf("Daemon running with PID %d\n", child1);
 
-            for (;;) {
-                got_child = xl_waitpid(child_waitdaemon, &status, 0);
-                if (got_child == child1) break;
+            got_child = xl_waitpid(child_waitdaemon, &status, 0);
+            if (got_child != child1) {
                 assert(got_child == -1);
-                perror("failed to wait for daemonizing child");
+                LOG("failed to wait for daemonizing child: %s", strerror(errno));
                 ret = ERROR_FAIL;
                 goto out;
             }
+
             if (status) {
                 libxl_report_child_exitstatus(ctx, XTL_ERROR,
                            "daemonizing child", child1, status);
@@ -2109,17 +2109,16 @@ start:
             exit(-1);
         }
 
-        CHK_ERRNO(( logfile = open(fullname, O_WRONLY|O_CREAT|O_APPEND,
-                                   0644) )<0);
+        CHK_ERRNO(logfile = open(fullname, O_WRONLY|O_CREAT|O_APPEND, 0644));
         free(fullname);
         free(name);
 
-        CHK_ERRNO(( nullfd = open("/dev/null", O_RDONLY) )<0);
+        CHK_ERRNO(nullfd = open("/dev/null", O_RDONLY));
         dup2(nullfd, 0);
         dup2(logfile, 1);
         dup2(logfile, 2);
 
-        CHK_ERRNO(daemon(0, 1) < 0);
+        CHK_ERRNO(daemon(0, 1));
         need_daemon = 0;
     }
     LOG("Waiting for domain %s (domid %d) to die [pid %ld]",