Fixed to sync the timeline only if the backend is available.

src/IDF/Scm.php

@@ -343,6 +343,7 @@ class IDF_Scm
         $key = 'IDF_Scm:'.$project->shortname.':lastsync'; 
         if (null === ($res=$cache->get($key))) {
             $scm = IDF_Scm::get($project);
+            if ($scm->isAvailable()) {
                 foreach ($scm->getChangeLog($scm->getMainBranch(), 25) as $change) {
                     IDF_Commit::getOrAdd($change, $project);
                 }
@@ -350,4 +351,5 @@ class IDF_Scm
             }
         }
     }
+}