wic: code cleanup: undefined variables

Fixed forgoten imports Wic_PartData and ImageError.
Removed unused and undefined variable syslinux_conf.

(From OE-Core rev: db0903ad89dcb655c0eec5ac6dce96aae26533da)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/kickstart/custom_commands/__init__.py

@@ -1,6 +1,7 @@
 from micpartition import Mic_Partition
 from micpartition import Mic_PartData
 from partition import Wic_Partition
+from partition import Wic_PartData
 
 __all__ = (
     "Mic_Partition",

scripts/lib/wic/plugins/source/bootimg-efi.py

@@ -27,6 +27,7 @@
 import os
 import shutil
 
+from wic.utils.errors import ImageError
 from wic import kickstart, msger
 from wic.utils import misc, fs_related, errors, runner, cmdln
 from wic.conf import configmgr
@@ -72,8 +73,6 @@ class BootimgEFIPlugin(SourcePlugin):
         grubefi_conf += "linux %s root=%s rootwait %s\n" \
             % (kernel, rootstr, options)
         grubefi_conf += "}\n"
-        if splashline:
-            syslinux_conf += "%s\n" % splashline
 
         msger.debug("Writing grubefi config %s/hdd/boot/EFI/BOOT/grub.cfg" \
                         % cr_workdir)

scripts/lib/wic/plugins/source/bootimg-pcbios.py

@@ -26,6 +26,7 @@
 
 import os
 
+from wic.utils.errors import ImageError
 from wic import kickstart, msger
 from wic.utils import misc, fs_related, errors, runner, cmdln
 from wic.conf import configmgr