perf tools: Remove unnecessary callchain cursor state restore on unmatch

If a new callchain branch doesn't match a single entry of the node that
it is given against comparison in append_chain(), then the cursor is
expected to be at the same position as it was before the comparison
loop.

As such, there is no need to restore the cursor position on exit in case
of non matching branches.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1389713836-13375-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>