(check_usage): Fixed a typo: it is an error if the number of strings

	is use change, not if they stay the same.

src/server/testsuite/config/leaks.exp

@@ -66,7 +66,7 @@ proc check_usage {test id} {
     set strings_usage [lindex $val 1]
 
     set succeed 1
-    if { [expr $strings_usage == $strings_base] } {
+    if { [expr $strings_usage != $strings_base] } {
         fail "$test (strings) See lyskomd.$id.\{usage,base\}"
         set succeed 0
     }