ci: explicitly pass --sysconfdir=/etc to configure

I spent some time trying to figure out why on CentOS my changes to
`/etc/rpm-ostreed.conf` didn't seem to have any effect. It turns out
that for some reason I didn't spend too much time looking into, the
autoconf in CentOS defaults to `${prefix}/etc` when `--prefix` is given.

This is also why I was under the erroneous assumption that D-Bus config
files were in `/usr/etc` in CentOS. This patch fixes that as well.

Closes: #1215
Approved by: cgwalters

ci/libbuild.sh

@@ -21,7 +21,7 @@ make() {
 
 build() {
     env NOCONFIGURE=1 ./autogen.sh
-    ./configure --prefix=/usr --libdir=/usr/lib64 "$@"
+    ./configure --prefix=/usr --libdir=/usr/lib64 --sysconfdir=/etc "$@"
     make V=1
 }
 

tests/vmcheck/overlay.sh

@@ -52,9 +52,7 @@ rm vmcheck/etc -rf
 # Now, overlay our built binaries & config files
 INSTTREE=/var/roothome/sync/insttree
 rsync -rlv $INSTTREE/usr/ vmcheck/usr/
-if [ -d $INSTTREE/etc ]; then # on CentOS, the dbus service file is in /usr
-  rsync -rlv $INSTTREE/etc/ vmcheck/usr/etc/
-fi
+rsync -rlv $INSTTREE/etc/ vmcheck/usr/etc/
 
 # ✀✀✀ BEGIN hack to get --keep-metadata
 if ! ostree commit --help | grep -q -e --keep-metadata; then