* hydra: handle case where logfile is empty

Dependencies

• [2] ZNKPGZHF hydra: error on buildpage for queued build
• [3] MPVX6MKX * hydra: on build page, show tail of log on first tab when buildstatus == 1 (this specific build failed)
• [4] HB3OHPJL hydra: in case of cached build, add link to build that built the storepath
• [*] LBNVQXUB * Build the /build stuff in a separate controller.

Change contents

• replacement in src/lib/Hydra/Controller/Build.pm at line 48
  [2.97]→[2.97:231](∅→∅),[2.231]→[3.201:288](∅→∅),[3.201]→[3.201:288](∅→∅)
  − if (defined $build->resultInfo && $build->resultInfo->buildstatus == 1 && $lastBuildStep && isValidPath($lastBuildStep->logfile)) {

  − my $path = $lastBuildStep->logfile;

  − $c->stash->{logtext} = `tail -n 50 $path`;

  − }
  [2.97]

  [3.249]
  + my $path = defined $lastBuildStep ? $lastBuildStep->logfile : "" ;

  + if (defined $build->resultInfo && $build->resultInfo->buildstatus == 1 && !($path eq "") && isValidPath($lastBuildStep->logfile)) {

  + $c->stash->{logtext} = `tail -n 50 $path`;

  + }