Updating onos-package to display error when karaf-assembly fails.

Also, temporarily adding snapshot repo to karaf-assembly and filed bug to remove it.

Change-Id: I63bf472b3a918beec46e1b1002a29dfcb6cb7253

@@ -70,7 +70,7 @@
     </dependencies>
     <repositories>
         <repository>
-            <!-- TODO move over to release snmp-core when it becomes available.-->
+            <!-- TODO move over to release snmp-core when it becomes available. ONOS-3646 -->
             <id>oss.sonatype.org-snapshot</id>
             <url>http://oss.sonatype.org/content/repositories/snapshots</url>
             <snapshots>

@@ -230,7 +230,9 @@ trap "rm -f $aux 2>/dev/null" EXIT
 [ -n "$M2_REPO" ] && args="-Dmaven.repo.local=$M2_REPO" || args=""
 cd $ONOS_ROOT/tools/package/karaf-assembly &&
   mvn $args clean install > $aux 2>&1 ||
-  ( echo "Failed to run karaf-assembly" && exit 1 )
+  ( cat $aux &&
+    printf "\nFailed to run karaf-assembly, which stages artifacts for offline deployments.\n" &&
+    exit 1 )
 
 # Before starting make sure the environment is clan - delete onos staging folder
 clean_stage_dir

@@ -33,6 +33,14 @@
 
     <description>ONOS Apache Karaf assembly definitions</description>
 
+    <!-- FIXME this is necessary until snmp moves to release artifacts ONOS-3646 -->
+    <repositories>
+        <repository>
+            <id>snapshot</id>
+            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+        </repository>
+    </repositories>
+
     <build>
         <plugins>
             <plugin>