StandardLockService : cache information

Cache the fact that DATABASECHANGELOGLOCK exists and is initialized,
otherwise we do the check every time we acquire or release a lock
StandardChangeLogHistoryService : cache information

Cache the fact that DATABASECHANGELOG exists and is initialized.
Also remove the ranChangeSetList check in hasDatabaseChangeLogTable()
because if you call getRanChangeSets() before DATABASECHANGELOG  is
created then hasDatabaseChangeLogTable() will wrongly return true
because the ranChangeSetList variable has already been initialized and
is no longer NULL.