bug#15848: 24.3.50; cperl-mode + which-function: Improve reporting (corner case)

[Jambunathan K]

24.3.50; cperl-mode + which-function: Inaccurate reporting (corner case)

See the attached screenshot.  Note the following

1. Cursor position in the top window. 

   In the bottom window, the cursor is well within the toplevel block of
   sub.

2. which-function field of the modeline.

Hint: Note the presence/absence of `=' (most likely from the =cut line above)

cperl-which-function-is-inaccurate.png
Description: PNG image

In GNU Emacs 24.3.50.4 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2013-11-09 on debian-6.05
Bzr revision: 115051 jan.h.d@swipnet.se-20131109111953-cysfi19meuidy96q
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
System Description:     Debian GNU/Linux 6.0.5 (squeeze)