perf tools: Save partial non-overlapping map

The librarization of the thread helpers between annotate and
report lost some perf report specifics.

thread__insert_map() had its most uptodate version in perf
report which cared about partial map overlapping. In case of
overlap between two maps, perf annotate's version removes the
whole old map without considering if it partially or
absolutely overlaps the new map.

We exported the odd version, change it by using the perf
report version.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1250607843-7395-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>