mockftpserver: drop .classpath files and update README.txt am: 7a7323460c am: dfa2060ad0 am: ec64f179b5 am: dfae9b3ae7 am: ecccd08d3a

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/mockftpserver/+/16495238

Change-Id: Ic9792d748e9eb2353b79d36480067ca4dfadf6ce