travis: Build openssl with --disable-strict
travis: Build openssl with --disable-strict

Current OpenSC git master gets compiler warnings in some buid
combinations, and that causes the whole build to fail. Since
our chain concerns libp11, build the OpenSC without -Werror.

dengert/libp11,OpenSC/libp11,mouse07410/libp11,mtrojnar/libp11,mouse07410/libp11,dengert/libp11,OpenSC/libp11,mtrojnar/libp11