kolab-util-sqlite: free()ing fixes
kolab-util-sqlite: free()ing fixes

* in kolab_util_sqlite_db_free(), set the KolabUtilSqliteDb
  path member to NULL after free()ing it
* in kolab_util_sqlite_db_open(), do not free() store_db_path
  unless there's an error condition (it gets bound to a
  KolabUtilSqliteDb later and is free()d there)

GNOME/evolution-kolab,GNOME/evolution-kolab