Do not consider keystore.metadata as a keystore on <= 4.0

On ESE startup, we determine the KMIP key identifier by looping through any keystores looking for the first keyname. This assumption made sense prior to adopting the v1 page layout.  Now that we have the metadata store, the keyidentifiers are more variable.  We should backport the exception used in v4.2 and later to ignore keystore.metadata in this loop.