fib: respect mfib entry flags on create with paths

fib: respect mfib entry flags on create with paths

When an mfib entry was created with both paths and entry_flags then
the entry flags were being ignored. If there are no paths then the
flags were passed into mfib_table_entry_update, but in the case where
the entry didn't exist and there were paths and flags, the entry was
created within mfib_table_entry_paths_update() which used a default
of MFIB_ENTRY_FLAG_NONE.

Pass the flags through into the mfib_table_entry_paths_update fn. All
existing callers other than the create case will now pass in
MFIB_ENTRY_FLAG_NONE.

Type: fix
Signed-off-by: Paul Atkins <patkins@graphiant.com>
Change-Id: I256375ba2fa863a62a88474ce1ea6bf2accdd456