When the list of candidates is empty use the previous implementation.

Author: hajoeichler

src/main/java/hudson/plugins/git/util/DefaultBuildChooser.java

@@ -104,6 +104,12 @@ public Collection<Revision> getCandidateRevisions(boolean isPollCall, String sin
                 revision.getBranches().add(new Branch(singleBranch, sha1));
                 candidateRevs.add(revision);
             }
+            // fallback to return given sha1 if the list of candidate revisions is empty
+            if (candidateRevs.isEmpty()) {
+                Revision revision = new Revision(sha1);
+                revision.getBranches().add(new Branch(singleBranch, sha1));
+                return Collections.singletonList(revision);
+            }
             return candidateRevs;
         } catch (GitException e) {
             // branch does not exist, there is nothing to build