Makefile: clean pyang-json-schema-plugin

Change-Id: I3b9ec2731f9bbc5add5c3c5ca6b67995c0a04c6f
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/Makefile b/Makefile
index 62643b0..695c49e 100644
--- a/Makefile
+++ b/Makefile
@@ -60,4 +60,4 @@
 	git clone https://github.com/cmoberg/pyang-json-schema-plugin
 
 clean:
-	$(Q)rm -rf build dist osm_im.egg-info deb deb_dist *.gz pyangbind $(OUT_DIR)
+	$(Q)rm -rf build dist osm_im.egg-info deb deb_dist *.gz pyangbind pyang-json-schema-plugin $(OUT_DIR)