Fix gssd ignore machine credentials for root

[Doug Nazar <nazard.michi@xxxxxxxxx>]

Commit 1c787f14 [gssd: scan for DIR: ccaches, too] changed the default 
prefix for the credential cache files. Update the check to ignore the 
machine credential file when running with -n (root ignores machine 
credentials).

Doug

--- utils/gssd/krb5_util.c	2013-05-11 00:33:08.054297810 -0400
+++ ../nfs-utils-1.2.7.new/utils/gssd/krb5_util.c	2012-11-11 18:01:23.000000000 -0500
@@ -231,7 +231,7 @@
 				continue;
 			}
 			if (uid == 0 && !root_uses_machine_creds && 
-				strstr(namelist[i]->d_name, "_machine_")) {
+				strstr(namelist[i]->d_name, "machine_")) {
 				printerr(3, "CC '%s' not available to root\n",
 					 statname);
 				free(namelist[i]);