Tell git to ignore tools/ssl-update
Tell git to ignore tools/ssl-update

This tools was recently added, but not added to .gitignore. Do
so now.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Helga Velroyen <2d0126b1ec6f9ec5cbec4a7012aa14faeaef10f5@google.com>

ganeti/ganeti,yiannist/ganeti,yiannist/ganeti,mbakke/ganeti,grnet/snf-ganeti,leshchevds/ganeti,bitemyapp/ganeti,ganeti/ganeti,onponomarev/ganeti,grnet/snf-ganeti,leshchevds/ganeti,yiannist/ganeti,mbakke/ganeti,onponomarev/ganeti,andir/ganeti,mbakke/ganeti,bitemyapp/ganeti,ganeti/ganeti,andir/ganeti,andir/ganeti,leshchevds/ganeti