Add openSUSE Leap 15.0

src/opensuse.ipxe

@@ -4,9 +4,8 @@
 # http://opensuse.org
 set distro opensuse
 menu openSUSE - ${arch} - Image Sig Checks: [${img_sigs_enabled}]
+item 15.0 openSUSE Leap 15.0
 item 42.3 openSUSE Leap 42.3
-item 42.2 openSUSE Leap 42.2
-item 42.1 openSUSE Leap 42.1
 item tumbleweed openSUSE tumbleweed
 choose version || goto opensuse_exit
 set dir ${opensuse_base_dir}/${version}/repo/oss