[#61007096] fix mms agent install to not clobber /usr/local/share

also:
- mms_agent.install_dir now correctly points to the actual install dir, and not its parent
- added 3 new attributes to better control munin
- now creates the parent install dir if it does not exist
- use chef's file cache instead of tmp
- update download link with (new) canonical url, and changed 10gen to mongodb
- version bump
[#61007096] code review:

- doc fixup
- mms agent download url is now an attribute
[#61007096] code review: better docs about mms-agent dir
[#61007096] make sure install_dir is recursively created if necessary
Merge pull request #6 from Kabam/mms-agent-fixes

[#61007096] fix mms agent install to not clobber /usr/local/share