netfilter: ebtables: put module reference when an incorrect extension is found

commit bcf49342 ("netfilter: ebtables: Fix extension lookup with
identical name") added a second lookup in case the extension that was
found during the first lookup matched another extension with the same
name, but didn't release the reference on the incorrect module.

Fixes: bcf49342 ("netfilter: ebtables: Fix extension lookup with identical name")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>