trace-cmd: Clear triggers before writing to them
trace-cmd: Clear triggers before writing to them

If a trigger exists and we try to add it to an event, it will fail
with a "-EEXIST" error. The triggers need to be cleared before
we write to them.

Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd