style(maas): s/get_reposebody/get_responsebody

I'm fairly sure this function refers to getting the body of an HTTP
response and not a state of relaxation or composure. See also
[HTTP referer](http://en.wikipedia.org/wiki/HTTP_referer). :)
Merge pull request #123 from ksheedlo/style-fix-getreposebody

style(maas): s/get_reposebody/get_responsebody