Removes the dependence with aptitude

Removes the dependence with aptitude by replacing
the call of:
  aptitude purge -y ~npackage by apt_get purge -y package*

Change-Id: I08875ffad9dc6293047827666f02453a355b16ea
Closes-Bug: 1281410
diff --git a/lib/rpc_backend b/lib/rpc_backend
index 3651bc0..34f576f 100644
--- a/lib/rpc_backend
+++ b/lib/rpc_backend
@@ -67,7 +67,7 @@
         sudo killall epmd || sudo killall -9 epmd
         if is_ubuntu; then
             # And the Erlang runtime too
-            sudo aptitude purge -y ~nerlang
+            apt_get purge -y erlang*
         fi
     elif is_service_enabled qpid; then
         if is_fedora; then