* installcheck/Installcheck/Rest.pm (): Better error if straman can't
  be forked.
* installcheck/Amanda_Rest_Configs.pl,
  installcheck/Amanda_Rest_Dles.pl,
  installcheck/Amanda_Rest_Dumps.pl,
  installcheck/Amanda_Rest_Labels.pl,
  installcheck/Amanda_Rest_Storages.pl,
  installcheck/Amanda_Rest_Storages_Labels.pl,
  installcheck/Amanda_Rest_Version.pl: Improve error message.


git-svn-id: https://svn.code.sf.net/p/amanda/code/amanda/trunk@5777 a8d146d6-cc15-0410-8900-af154a0219e0