perf report: Remove duplicate annotate choice in branch view mode

This patch removes the duplicated annotate selection when
browsing in branch view mode. If the sym and dso oof the branch
source and target are the same, then only one annotate choice is
proposed.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331565210-10865-2-git-send-email-eranian@google.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>