tools lib traceevent: Rename LIB_FILE to LIB_TARGET

To ease up following patch.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-zpv5gd8y7clwrhh6dq03ucd5@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>