Do not enter password of transifex at command line by security reason

Any command line options could be accessed by other users.
`tx init` command has interaction interface.
It should be used by all users by default.

--HG--
branch : tk0miya/do-not-enter-password-of-transifex-at-co-1404623350328
Fix `tx init` command again.

--HG--
branch : tk0miya/do-not-enter-password-of-transifex-at-co-1404623350328
Merged in tk0miya/sphinx/tk0miya/do-not-enter-password-of-transifex-at-co-1404623350328 (pull request #253)

Do not enter password of transifex at command line by security reason