nf_conntract update

The recipe was using a strict integer check, this made it impossible
for the resource provider to use as the resource provider only accepts
string input.

(cherry picked from commit efccacd3b3575f067bf874800d6a6c7c3cb7ae2a)
Merge pull request #170 from claco/nf-conntrack-update

Merged automatically by jenkins after successful build test