modify enable-wterl to avoid adding wterl repeatedly

Before modifying files to add wterl, check to make sure the addition hasn't
already been made. Also change to do a stagedevrel build instead of a
devrel build.

enable-wterl

@@ -35,7 +35,7 @@ fi
 rebar get-deps
 
 file=./deps/riak_kv/src/riak_kv.app.src
-if ! grep -q hanoidb $file ; then
+if ! grep -q hanoidb $file && ! grep -q wterl $file ; then
     echo
     echo "Modifying $file, saving the original as ${file}.orig ..."
     perl -i.orig -pe '/\bos_mon,/ && print qq(                  wterl,\n)' $file
@@ -51,7 +51,7 @@ fi
 rebar get-deps
 
 rm -rf dev
-make all devrel
+make all stagedevrel
 
 echo
 echo 'Modifying all dev/dev*/etc/app.config files, saving originals with .orig suffix...'