Added configuration options for kernel and initrd selection during KVM build

Some distributions have no initrd images compatible with KVM builds and
sometimes we need to use not system kernel version.

New options in configuration file:
- build-kernel -- kernel used for VM builds
- build-initrd -- initrd image used for VM builds

osc/build.py

@@ -991,6 +991,11 @@ def main(apiurl, opts, argv):
                 if os.access(build_root, os.W_OK) and os.access('/dev/kvm', os.W_OK):
                     # so let's hope there's also an fstab entry
                     need_root = False
+                if config['build-kernel']:
+                    vm_options += [ '--vm-kernel=' + config['build-kernel'] ]
+                if config['build-initrd']:
+                    vm_options += [ '--vm-initrd=' + config['build-initrd'] ]
+
             build_root += '/.mount'
 
         if config['build-memory']:

osc/conf.py

@@ -112,6 +112,8 @@ DEFAULTS = {'apiurl': 'https://api.opensuse.org',
             'build-vmdisk-rootsize': '',        # optional for VM builds
             'build-vmdisk-swapsize': '',        # optional for VM builds
             'build-vmdisk-filesystem': '',        # optional for VM builds
+            'build-kernel': '',                 # optional for VM builds
+            'build-initrd': '',                 # optional for VM builds
 
             'build-jobs': _get_processors(),
             'builtin_signature_check': '1',     # by default use builtin check for verify pkgs
@@ -227,6 +229,12 @@ apiurl = %(apiurl)s
 # e.g. /var/tmp/FILE.swap
 #build-swap = /var/tmp/FILE.swap
 
+# build-kernel is the boot kernel used for VM builds
+#build-kernel = /boot/vmlinuz
+
+# build-initrd is the boot initrd used for VM builds
+#build-initrd = /boot/initrd
+
 # build-memory is the amount of memory used in the VM
 # value in MB - e.g. 512
 #build-memory = 512