bitbake.conf: Remove obsolete/unused MIRROR cruft

bitbake.conf: Remove obsolete/unused MIRROR cruft

ADOBE_MIRROR, HANDHELDS_CVS and E_SVN were broken links and not used by
any recipe in oe-core.

FREEDESKTOP_CVS is no longer useful because all the source code that
matters is in git; no recipe in oe-core still uses the CVS repository.

E_MIRROR, FREEBSD_MIRROR, FREESMARTPHONE_GIT still point to valid-seeming
locations but there are no recipes in oe-core that use them.  Any layers
which need these variables can define them for themselves.

GPE_SVN, GPE_EXTRA_SVN, GPEPHONE_MIRROR and GPEPHONE_SVN are not used by
any recipe in oe-core and the corresponding projects seem to be mostly
dead upstream.  Again, any layers which still wish to use these variables
can define them locally.

All the above are just wasting space in bitbake's datastore and would be
better deleted.

(From OE-Core rev: 3b333896c71689c664475d53daed52404bf6b21b)

Signed-off-by: Phil Blundell <philb@gnu.org>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>