Remove current.txt files

Nothing depends on these anymore. The same data is available through
the build artifact framework-base-api-current.txt.

Bug: 171029603
Test: m checkbuild
Change-Id: I13d9373f7174e2ff2bc54122a1fcfae0b7f7293c
Merged-In: I13d9373f7174e2ff2bc54122a1fcfae0b7f7293c
(cherry picked from commit b5ec8a9a1052a9d5c860e44fd9159488d356ab1c)
3 files changed