adding pexpect to pip packages

Change-Id: I4fe56abe110b20e770967ca40ebaf1230f89f877
diff --git a/packer/provision/basebuild.sh b/packer/provision/basebuild.sh
index 34c1a3b..5cbe77c 100644
--- a/packer/provision/basebuild.sh
+++ b/packer/provision/basebuild.sh
@@ -75,7 +75,9 @@
         robotframework \
         robotframework-sshlibrary \
         robotframework-requests \
-        robotframework-httplibrary
+        robotframework-httplibrary \
+	pexpect \
+	pyyaml
 
     # install npm modules
     npm install -g \