adding a single comma at the end of the options list confuse the module

it start to duplicate line, because this create
a empty option in the list, and so the module add a new line along the previous
one. See

>>> ' a,b, '.strip().split(',')
['a', 'b', '']
sort the option_key to have a constant predictable line
make sure that options are quoted, as people can add a shell
script there with a comma that would produce invalid configuration
upon being wrote again
Fixing up authorized_keys to accept comments with spaces
Merge branch 'fix_autorized_keys' of https://github.com/mscherer/ansible into mscherer-fix_autorized_keys