cros_workon: allow a stop on a dead package

cros_workon: allow a stop on a dead package

Previously, you could not stop working on a package if its ebuild had
been removed. This fixes this issue by skipping canonicalization if the
package name exactly matches a name in the workon file.

BUG=11214
TEST=See below.

(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic list
sys-kernel/chromeos-kernel
(cros-chroot) msb@msb ~/trunk/src/scripts $ echo "=foo/bar-9999" >> ~/trunk/.config/cros_workon/x86-generic
(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic list
sys-kernel/chromeos-kernel
foo/bar
(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic stop foo/bar
!!! No packages matching 'foo/bar'
WARNING: error looking up package foo/bar
ERROR  : Error parsing package list

*** I made changes to cros_workon here

(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic list
sys-kernel/chromeos-kernel
foo/bar
(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic stop foo/bar
INFO   : Stopped working on 'foo/bar' for 'x86-generic'
(cros-chroot) msb@msb ~/trunk/src/scripts $ ./cros_workon --board x86-generic list
sys-kernel/chromeos-kernel

Change-Id: Id5cbd2b145b4d0fca96cfb245f1ac99e0b3cbdf3

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=07f9209

[davidjames, 2011-01-24 21:56:54]

LGTM, please file a bug :)