Remove external/blktrace

It hasn't been touched since 2009, the Makefiles are disabled,
and it doesn't build when enabled.

Test: none
Change-Id: I4d380e837235a2b26c8c44842b0e75b7a560d93b
1 file changed
tree: 37c608541847d6566742edfcc31e01c15ae9d0d8
  1. GLOBAL-PREUPLOAD.cfg
  2. aosp-master-with-phones.xml
  3. default.xml