pprof: fix tmp filename path construction
pprof: fix tmp filename path construction

The pprof handler was trying to store the profile data in
/tmp/kudu_cpu_profile/<pid>.<rand>. The kudu_cpu_profile directory is unlikely
to exist, which makes the path handler fail.

This seems to have been an accidental regression in
d20b44704033d46be76ce4bfa55df09251b45520.

This restores the prior behavior of /tmp/kudu_cpu_profile.<pid>.<rand>

Change-Id: I555037cb2ee59ef3735e209816def23d8bed856b
Reviewed-on: http://gerrit.cloudera.org:8080/3029
Tested-by: Kudu Jenkins
Reviewed-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>

andrwng/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,andrwng/kudu,andrwng/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,cloudera/kudu,EvilMcJerkface/kudu,helifu/kudu,helifu/kudu,helifu/kudu,cloudera/kudu,cloudera/kudu,InspurUSA/kudu,InspurUSA/kudu,helifu/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,EvilMcJerkface/kudu,cloudera/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,helifu/kudu,EvilMcJerkface/kudu,andrwng/kudu,helifu/kudu,helifu/kudu,andrwng/kudu,EvilMcJerkface/kudu,cloudera/kudu,EvilMcJerkface/kudu,andrwng/kudu,InspurUSA/kudu,cloudera/kudu,andrwng/kudu,andrwng/kudu,InspurUSA/kudu,helifu/kudu,InspurUSA/kudu,InspurUSA/kudu,InspurUSA/kudu,cloudera/kudu