policy: fix bug of multi policy application
policy: fix bug of multi policy application

when multiple policies with modification actions are configured, use a path
structure which was applied to the previous policy.

Signed-off-by: Wataru Ishida <15703620d0b11e835ab4f34ebf88f2f40cce783e@lab.ntt.co.jp>

fujita/gobgp,a16/gobgp,j-kato/gobgp,ishidawataru/gobgp,j-kato/gobgp,Dipsingh/gobgp,tamihiro/gobgp,osrg/gobgp,ishidawataru/gobgp,a16/gobgp,a16/gobgp,fujita/gobgp,osrg/gobgp,a16/gobgp,osrg/gobgp,a16/gobgp,a16/gobgp,fujita/gobgp,osrg/gobgp,j-kato/gobgp,tamihiro/gobgp,Dipsingh/gobgp,fujita/gobgp,ishidawataru/gobgp,tamihiro/gobgp,tamihiro/gobgp,Dipsingh/gobgp,a16/gobgp