ejabberd: new package.

[Thomas:
 - Adjust the comment about the dependency on erlang
 - Fix license to be 'GPLv2+ with OpenSSL exception' and not just 'GPLv2+'
 - Use double quotes instead of simple quotes in the .mk file.
 - Don't use the EJABBERD_MAKE_ENV variable, since it's not defined
   anywhere.
 - Remove the 0007-fix-init.patch patch, since we're not using the
   init script provided by ejabberd, and rename
   0008-fix-install-permissions.patch to
   0007-fix-install-permissions.patch.]

Signed-off-by: Johan Oudinet <johan.oudinet@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>