res_pjsip_phoneprov_provider: Add missing dependency on pjproject.


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@425216 f38db490-d61c-443f-a65b-d21fe96a405b
res/res_phoneprov: Bail on registration if res_phoneprov didn't load

If res_phoneprov failed to fully load (due to not being configured), the
providers container will be NULL. If a module attempts to register a phone
provisioning provider, it should check for the presence of the container.
If there is no providers container, it should return an error.

This patch makes the ast_phoneprov_provider_register function do that...
otherwise this would be a silly commit message.


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@425220 f38db490-d61c-443f-a65b-d21fe96a405b