Rename Google verification file to use md extension

Change-Id: I89a7c6b7964642833549673547ae74d3aa2cc358
diff --git a/googlebdbd14417c92a607.html b/googlebdbd14417c92a607.md
similarity index 100%
rename from googlebdbd14417c92a607.html
rename to googlebdbd14417c92a607.md