Adds Status test case with the SecServerSignature being used

If SecServerSignature is used ModSecurity should send the real data, not the
one informed to SecServerSignature.
Originally reported by: Linas
Trims long `apache version' in the status call

As reported at #714 status calls with long `apache version' name was broken.
DNS queries cannot be so long. This field is now limited to 25 characters
which is a valid size when encoded into base32
Using real server signature on status call

On Apache platform the server signature can be replaced using the
SecServerSignature directive. Status call was using the signature informed by
this directive instead of using the original one. As reported at #702.