- Fixed 'instance_create' would return -4 (party already instancing) when the requested party was not found.
- 'instance_create' return value -2 now means 'party not found' rather than 'missing parameter'.
git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@14809 54d463be-8e91-2dee-dedb-b68131a5f0ec