ofproto-dpif: Never wildcard dl_type for "normal" action.

ofproto-dpif: Never wildcard dl_type for "normal" action.

The is_gratuitous_arp() function is occasionally called when
processing the "normal" action.  The previous code only disabled
wildcarding the dl_type field when the function was called, but
since it runs occasionally, it could lead to inconsistencies in the
facet table.  This commit causes the dl_type to never be wildcarded
when the "normal" action is used.

Signed-off-by: Justin Pettit <jpettit@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>