selftest/container: fix IMAGE_FEATURES assignment

Assigning IMAGE_FEATURES="" in local.conf doesn't actually do anything
useful, as bitbake.conf has IMAGE_FEATURES += EXTRA_IMAGE_FEATURES after
the include of local.conf.

In this test case, this results in IMAGE_FEATURES still using
EXTRA_IMAGE_FEATURES, so the image contains the files installed by the
post-install-logging feature.

As the intention here is that container-test-image is as minimal as
possible, move the IMAGE_FEATURES assignment into the image itself so
it actually works, and update the expected file list to remove the
post-install-logging files.

(From OE-Core rev: c65349e1238ddc6634dfa4759c57e6168a355200)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-selftest/recipes-test/container-image/container-test-image.bb

@@ -4,5 +4,6 @@ LICENSE = "MIT"
 
 IMAGE_FSTYPES = "container"
 IMAGE_LINGUAS = ""
+IMAGE_FEATURES = ""
 
 inherit core-image

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

@@ -42,7 +42,6 @@ class ContainerImageTests(OESelftestTestCase):
         self.write_config("""PREFERRED_PROVIDER_virtual/kernel = "linux-dummy"
 IMAGE_FSTYPES = "container"
 PACKAGE_CLASSES = "package_ipk"
-IMAGE_FEATURES = ""
 IMAGE_BUILDINFO_FILE = ""
 INIT_MANAGER = "sysvinit"
 IMAGE_INSTALL:remove = "ssh-pregen-hostkeys"
@@ -55,8 +54,6 @@ IMAGE_INSTALL:remove = "ssh-pregen-hostkeys"
         expected_files = [
                     './',
                     '.{bindir}/theapp',
-                    '.{sysconfdir}/default/',
-                    '.{sysconfdir}/default/postinst',
                     '.{sysconfdir}/ld.so.cache',
                     '.{sysconfdir}/timestamp',
                     '.{sysconfdir}/version',