defect 3282: use the /var/run/xcatd.pid to store the main pid of xcat if no pidfile is specified with -p flag

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@14873 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/sbin/xcatd

@@ -109,6 +109,9 @@ GetOptions(
   'foreground|f' => \$foreground
 );
 
+unless ($pidfile) {
+  $pidfile = "/var/run/xcatd.pid";
+}
 
 #start syslog if it is not up
 if (xCAT::Utils->isLinux()) {