Make "set/show debug coff_pe_read" a zuinteger instead of uinteger.

Being a uinteger means you can't disable debug output after enabling it...

  (gdb) show debug coff_pe_read
  Coff PE read debugging is 0.
  (gdb) set debug coff_pe_read 0
  (gdb) show debug coff_pe_read
  Coff PE read debugging is unlimited.
  (gdb)

gdb/
2013-03-27  Pedro Alves  <palves@redhat.com>

	* coff-pe-read.c (_initialize_coff_pe_read): Make the command
	zuinteger instead of uinteger.
Rename "set debug coff_pe_read" command to "set debug coff-pe-read".

Hyphens are much more common than underscores in command names.

gdb/
2013-03-27  Pedro Alves  <palves@redhat.com>

	* coff-pe-read.c (_initialize_coff_pe_read): Rename "set debug
	coff_pe_read" command to "set debug coff-pe-read".