tools lib traceevent: Fix clean target in Makefile

Dependency files were not cleaned up. Add missing space to fix the issue.

Signed-off-by: Konstantin Stepanyuk <konstantin.stepanyuk@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1340833934-18783-1-git-send-email-konstantin.stepanyuk@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>