Add error message to build description

Change-Id: Ifffce007fbe9d3bc47ea57c30ee652b5e0bdb680
diff --git a/git-mirror-pipeline.groovy b/git-mirror-pipeline.groovy
index 10fa9a0..9378c9d 100644
--- a/git-mirror-pipeline.groovy
+++ b/git-mirror-pipeline.groovy
@@ -17,6 +17,7 @@
     } catch (Throwable e) {
        // If there was an error or exception thrown, the build failed
        currentBuild.result = "FAILURE"
+       currentBuild.description = e.message
        throw e
     } finally {
        common.sendNotification(currentBuild.result,"",["slack"])