More minor tidy of OSX docs

Changes are pretty simple. 1.0.x ES not available on homebrew at present but I figure that might catch up so didn't delete the homebrew instructions, just noted to check.

Outstanding questions are where to document the setting of es.host in the .ini files and/or whether to change default to be localhost instead of dokku. I think that leaving the default to be dokku might be helpful but then there should perhaps be a note in INSTALL.rst  (as setting is platform independent) about changing the .ini to use local ES?