core: server fails to load on wrong custom property regex

On server load we initialize custom properties regex-es,
in-case a regex doesn't match the pattern PatternSyntaxException
is caught, but rethrown somehow, and this fails
InitBackendServicesOnStartup.create()

Change-Id: I086662cc6cfbb7ade65111a55ef736ca02b33ca8
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>