bug#5549: 23.1; icalender-export-region fails to recognize times like 0:30

[karme <karme@karme.de>]

example ~/diary file:
Feb 9, 2010 0:15-0:30 test
Feb 9, 2010 1:00-1:30 test

M-x mark-whole-buffer
M-x icalender-export-region /tmp/test <RET>
M-x find-file /tmp/test:

BEGIN:VCALENDAR
PRODID:-//Emacs//NONSGML icalendar.el//EN
VERSION:2.0
BEGIN:VEVENT
UID:emacs19312442528474988
DTSTART;VALUE=DATE:20100209
DTEND;VALUE=DATE:20100210
SUMMARY:0:15-0:30 test
END:VEVENT
BEGIN:VEVENT
UID:emacs19312442528481099
DTSTART;VALUE=DATE-TIME:20100209T010000
DTEND;VALUE=DATE-TIME:20100209T013000
SUMMARY:test
END:VEVENT
END:VCALENDAR

Note how the the first entry is different from the second one. The time
has not been recognized.

In GNU Emacs 23.1.1 (x86_64-pc-linux-gnu)
 of 2010-01-27 on brahms, modified by Debian
configured using `configure  '--build=x86_64-linux-gnu' '--host=x86_64-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim' '--with-x=no' 'build_alias=x86_64-linux-gnu' 'host_alias=x86_64-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  server-mode: t
  savehist-mode: t
  iswitchb-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC 
O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B 
ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC 
O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B 
ESC O B ESC O B ESC O B C-x b d i a RET C-a C-k C-y 
ESC O A RET ESC O A C-y C-k ESC O A ESC O C ESC O C 
ESC O C ESC O C ESC O C ESC O C ESC O C ESC O C ESC 
O C ESC O C ESC O C ESC O C ESC O C ESC O C ESC O D 
DEL 0 ESC O C ESC O C ESC O C ESC O C ESC O C ESC O 
C ESC O D DEL 0 C-a C-x C-s ESC O B ESC O A C-@ ESC 
O B ESC O B ESC x ESC O A RET ESC O A RET C-x C-f C-a 
C-k 7 DEL ( t DEL DEL / t TAB t TAB RET ESC < C-@ ESC 
O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B 
ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC 
O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B 
C-w C-x C-s ESC x r e p TAB o TAB b DEL r t TAB RE
T

Recent messages:
Mark set [2 times]
Saving file /home/karme/diary...
Wrote /home/karme/diary
Mark activated
Saving file /tmp/test...
Wrote /tmp/test
Mark set [2 times]
Saving file /tmp/test...
Wrote /tmp/test
Making completion list... [2 times]