clean.sh needs to call "run_phase clean" for external plugins

Change-Id: I67b970992479e50dc054f8c4a77a20e724e3e305
diff --git a/clean.sh b/clean.sh
index 4f8c051..ad4525b 100755
--- a/clean.sh
+++ b/clean.sh
@@ -76,6 +76,8 @@
 # ==========
 
 # Phase: clean
+run_phase clean
+
 if [[ -d $TOP_DIR/extras.d ]]; then
     for i in $TOP_DIR/extras.d/*.sh; do
         [[ -r $i ]] && source $i clean