Move to .md files for even trivial documentation.

So it's automatically displayed for folks browsing the source.

Bug: N/A
Test: N/A
Change-Id: Ie9b190072ebdf0faf06cc1fd7b3467c031056753
diff --git a/minadbd/README.txt b/minadbd/README.md
similarity index 100%
rename from minadbd/README.txt
rename to minadbd/README.md