Makefile to generate new SSL certificates

Change-Id: I20d438282bb952aea65e86485707bd79b218eddc
diff --git a/pki/.gitignore b/pki/.gitignore
new file mode 100644
index 0000000..2a1c9a6
--- /dev/null
+++ b/pki/.gitignore
@@ -0,0 +1,2 @@
+root_ca
+voltha.csr