make the primary gpg keylength == the subkey length

Horde always generates 1024 bit primary keys. This should be considered
a bug, since by the semantic of all other key generating tools, key
length concerns primary and sub-key.

Signed-off-by: Michael M Slusarz <slusarz@horde.org>

Bug #12099
generate rsa/rsa keys instead of dsa

in accordance with gnupg we should create rsa keys instead of
deprecated dsa/el-gamal keys.

see:
http://lists.gnupg.org/pipermail/gnupg-devel/2009-May/025079.html

Signed-off-by: Michael M Slusarz <slusarz@horde.org>

Bug #12099
Remove outdated phpdoc
prefer sha-2 algos over sha-1 in key generation

following the new defaults of gpg.

see
http://lists.gnupg.org/pipermail/gnupg-announce/2009q3/000291.html
below "What's New"

Signed-off-by: Michael M Slusarz <slusarz@horde.org>

Bug #12099
[mms] Improve security in PGP key generation (Request #12099).