Fix for pptpsetup without specifing --password parameter

[franzo15]

Use also perl module Term::ReadKey in order to prevent display the password in clear text

[quozl]

Thanks. Reviewed.

• removal of trailing whitespace has been lost, f449742,
• accept passwords with quotes has been lost, e62bfa7,
• indentation style has changed, inconsistent within file,
• version changed but no explanation in commit message; it hasn't changed since 2006, does this mean you taking on responsibility to maintain this? I've been thinking of removing pptpsetup for the next release, now that Network Manager deals with configuration on desktop systems.