Disallow colon in default value https://sourceforge.net/p/webadmin/bugs/4839/

custom/custom-lib.pl

@@ -377,6 +377,7 @@ for($i=0; defined($name = $in{"name_$i"}); $i++) {
 			$in{"opts_$i"} =~ /\|$/ || -r $in{"opts_$i"} ||
 				&error(&text('save_eopts', $i+1));
 			}
+		$in{"opts_$i"} =~ /:/ && &error(&text('save_eopts2', $i+1));
 		push(@{$cmd->{'args'}}, { 'name' => $name,
 					  'desc' => $in{"desc_$i"},
 					  'type' => $in{"type_$i"},

custom/lang/en

@@ -78,6 +78,7 @@ save_etimeout=Missing or invalid maximum time to wait
 save_eusermin=Commands that run on other servers cannot be run from Usermin
 save_eformat=Invalid output MIME type
 save_eopts=Missing options file for parameter $1
+save_eopts2=Options file or default value for parameter $1 cannot contain :
 
 run_err=Failed to execute command
 run_ecannot=You are not allowed to run this command