Throwing an exception incase the template service couldnt register template.

server/src/com/cloud/template/TemplateManagerImpl.java

diff --git a/server/src/com/cloud/template/TemplateManagerImpl.java b/server/src/com/cloud/template/TemplateManagerImpl.java
index 10ff77f..af35dd8 100755
--- a/server/src/com/cloud/template/TemplateManagerImpl.java
+++ b/server/src/com/cloud/template/TemplateManagerImpl.java
@@ -384,7 +384,7 @@
 
             return response;
         } else {
-            return null;
+            throw new CloudRuntimeException("Unable to register template.");
         }
     }