bug#15436: 24.3.50; reads ~/.mailcap only once

[Gregor Zattler]

Dear Emacs Developers, 

Emacs reads ~/.mailcap only once, does not recognize later
changes in this configuration file even if made with Emacs in the
same session.  This happens with Emacs23 and Emacs-snapshot.  I
consider this behaviour a bug.  Quitting Emacs and starting anew
forces reload of ~/.mailcap.

How to reproduce:

When opening a file link to say an image or PDF document within
org-mode via C-u C-u C-c C-o Emacs reads (in default
configuration) ~/.mailcap in search for a application to open the
file with.  If one then changes this ~/.mailcap, saves it and opens
the same file again it is opened via the mailcap entry before the
change.

Thanks for your attention, Gregor