fix for issue sbt#529

- use numeric rather than string test in conditional
- add missing semicolon

src/main/resources/com/typesafe/sbt/packager/archetypes/java_server/rpm/postun-template

@@ -4,7 +4,7 @@ ${{control-functions}}
 
 # Scriptlet syntax: http://fedoraproject.org/wiki/Packaging:ScriptletSnippets#Syntax
 # $1 == 1 is upgrade and $1 == 0 is uninstall
-if [[ $1 == 0 ]]
+if [ $1 -eq 0 ] ;
 then
     echo "Try deleting system user and group [${{daemon_user}}:${{daemon_group}}]"
     if getent passwd | grep -q "^${{daemon_user}}:";