Removed debugging
Added checks for GPG_AGENT_INFO.

If the environment variable GPG_AGENT_INFO is not set, try to find the
GPG agent information for the currently running reprepro_watch process.

If that is not found, then exit out with non-zero status, because it's
not possible to continue.
Updated fingerprint fetching.

Even on lucid, two --fingerprint arguments are needed.
Added set -e to exit on first error.