Update install.rst
Update install.rst

 - Changed git url to https scheme, which is more compatible if you install autojobs on a server with unconfigured git account.
 - Give User a hint which values could be used for $versiontag
ptnapoleon/jenkins-autojobs,ptnapoleon/jenkins-autojobs,gvalkov/jenkins-autojobs,gvalkov/jenkins-autojobs,PaulKlumpp/jenkins-autojobs,PaulKlumpp/jenkins-autojobs