oeqa selftest wic.py: fix missing ext4 image

test_rawcopy_plugin fails if machine does not build
ext4 images by default. Make the ext4 image build
explicit in the test. Fixes test on genericarm64 machine
which defaults to wic image only.

(From OE-Core rev: 0344b9e7949ef854b09deb0874a45cde2861f55b)

Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/wic.py

@@ -1180,6 +1180,10 @@ class Wic2(WicTestCase):
             self.assertEqual(1, len(out))
 
     def test_rawcopy_plugin(self):
+        config = 'IMAGE_FSTYPES = "ext4"\n'
+        self.append_config(config)
+        self.assertEqual(0, bitbake('core-image-minimal').status)
+        self.remove_config(config)
         self._rawcopy_plugin('ext4')
 
     def test_rawcopy_plugin_unpack(self):