mysql, pgsql and svn handlers: fixed inversed vsname emptyness test

ChangeLog

 version 0.9.4 -- unreleased
+    handler changes
+	mysql, pgsql, svn: fixed inversed vsname emptyness check
     lib changes
 	vserver:
 	 . init_vservers: fixed Debian bug #351083 (improper readlink syntax)

handlers/mysql

@@ -24,7 +24,7 @@ getconf configfile /etc/mysql/debian.cnf
 local usevserver=no
 local vroot
 if [ $vservers_are_available = yes ]; then
-   if [ ! -z "$vsname" ]; then
+   if [ -n "$vsname" ]; then
       # does it exist ?
       if ! vservers_exist "$vsname" ; then
          fatal "The vserver given in vsname ($vsname) does not exist."

handlers/pgsql

@@ -15,7 +15,7 @@ localhost=`hostname`
 local usevserver=no
 local vroot
 if [ $vservers_are_available = yes ]; then
-   if [ -z "$vsname" ]; then
+   if [ -n "$vsname" ]; then
       # does it exist ?
       if ! vservers_exist "$vsname" ; then
          fatal "The vserver given in vsname ($vsname) does not exist."

handlers/svn

@@ -16,7 +16,7 @@ error=0
 local usevserver=no
 local vroot
 if [ $vservers_are_available = yes ]; then
-   if [ -z "$vsname" ]; then
+   if [ -n "$vsname" ]; then
       # does it exist ?
       if ! vservers_exist "$vsname" ; then
          fatal "The vserver given in vsname ($vsname) does not exist."