ipaservice: Fix idempotent behavior for principal aliases.

When creating the lists to add/remove principal aliases, if the realm
was not specified, the alias would be used as it did not matched the
existing one, which has the realm part.

This patch fixes the add/del list creation by adding the current API
realm to each alias that does not have the realm part and then use
this modified list to be compared against the existing principal list.

This change also allows the use of the whole list in a single call to
the IPA API to add/remove the principals, instead of a call for every
one item in the list.