[PATCH] dwarf2read.c (peek_die_abbrev): Improve error message text.

[Doug Evans]

Doug Evans writes:
 > Hi.
 > 
 > This patch improves the text of an error message.
 > I happened to trip over this, and it was useful
 > to know the bogus CU from the error text.
 > 
 > 2014-11-26  Doug Evans  <dje@google.com>
 > 
 > 	* dwarf2read.c (peek_die_abbrev): Improve error message text.

Committed.