perf completion: Don't dictate perf install location

The statement

  have perf

limits the locations in which to look for the perf program.  Moreover,
it depends on the bash-completion package to be installed.  Replace it
with a call to `type perf`.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1372941691-14684-2-git-send-email-artagnon@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bash_completion

@@ -19,7 +19,7 @@ __ltrim_colon_completions()
 	fi
 }
 
-have perf &&
+type perf &>/dev/null &&
 _perf()
 {
 	local cur prev cmd