Adds Fedora 25 release

src/fedora.ipxe

@@ -12,6 +12,7 @@ clear ova
 set os Fedora
 menu Fedora - ${arch} - Image Sig Checks: [${img_sigs_enabled}]
 item --gap Latest Releases
+item 25 ${space} ${os} 25
 item 24 ${space} ${os} 24
 item 23 ${space} ${os} 23
 item 22 ${space} ${os} 22