I found the answer. Not sure why this fixes it, but all I had to do was create an hgrc file in the .hg directory of the repository in question (not the local cloned dir), and add:
[web] allow_push = *
In case anyone finds this answer while trying to debug a different part of the setup, here is a tutorial for the whole setup of Mercurial on Yosemite.
http://www.curvingspace.com/2014/11/05/mercurial-on-yosemite/