task#1847 - smail fixes:

- getRevision writes git output to log (requires enabled debugging to see it)
- added check for tmpdir

public_html/deployment/classes/vcs.git.class.php

@@ -228,7 +228,7 @@ class vcs implements iVcs {
             $sGitCmd.='git ls-remote --heads --tags origin 2>&1 ;';
             $this->log(__FUNCTION__." start command $sGitCmd");
             exec($sGitCmd, $aOutput, $iRc);
-            $this->log(__FUNCTION__." end command $sGitCmd");
+            $this->log(__FUNCTION__." end with rc=$iRc ", ($iRc==0 ? 'info':'error'));
             if ($iRc == 0) {
 
                 // use cache that getCommitmessageByBranch can access it