error when generating documentation

Hello, that's on the 2.2-beta on OS X

make doc results in the following error

Failed to document '@load base/protocols/ssl' in file: policy^protocols^ssl^expiring-certs.rst
error in /Users/mpurzynski/Downloads/bro-2.2-beta/scripts/policy/protocols/ssl/expiring-certs.bro, line 5: can't open /Users/mpurzynski/Downloads/bro-2.2-beta/scripts/base/protocols/ssl/__load__.bro
make[4]: *** [doc/rest_output/test-all-policy.rst] Error 1
make[3]: *** [doc/scripts/CMakeFiles/restdoc.dir/all] Error 2
make[2]: *** [doc/CMakeFiles/doc.dir/rule] Error 2
make[1]: *** [doc] Error 2
make: *** [doc] Error 2

Try raising `ulimit -n`, the shell limit for max number of open files (and I've already got a pending change to improve the error message for this case).

- Jon