kdump-steamos: Move configuration file out of /etc

This patch main goal is to "un-Debianize" the configuration file
for kdump-steamos - thanks Emil (@xexaxo) for the discussions; it
is with a bit of a heavy heart I do that, but let's comply with the
modern distros ;-)

We hereby put the config file in a more standard path: /usr/share.
Usually users could override that with /etc/ file, but not in this
case, or at least, not for now. Kdump/pstore is expected to work
quietly, with no users' interference. Advanced users might want to
play with the configs though; and those can just go ahead and edit
the /usr/share/kdump/kdump.conf - it's all documented in the README.

In the future we can improve that by having the override mechanism
with the /etc file, let's see if we have a demand for that.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>

kdump-load.sh

@@ -46,12 +46,12 @@ grub_update() {
 	fi
 }
 
-if [ ! -s "/etc/default/kdump" ]; then
-	logger "kdump-steamos: /etc/default/kdump not present - aborting..."
+if [ ! -s "/usr/share/kdump/kdump.conf" ]; then
+	logger "kdump-steamos: /usr/share/kdump/kdump.conf is missing, aborting."
 	exit 0
 fi
 
-. /etc/default/kdump
+. /usr/share/kdump/kdump.conf
 
 #  Find the proper mount point for /home:
 DEVN_MOUNTED="$(findmnt "${MOUNT_DEVNODE}" -fno TARGET)"
@@ -77,7 +77,7 @@ if [ "$1" = "clear" ]; then
 	exit 0
 fi
 
-#  Pstore-RAM load; if it is configured via /etc/default/kdump and fails
+#  Pstore-RAM load; if it is configured via /usr/share/kdump/kdump.conf and fails
 #  to configure pstore, we still try to load the kdump. We try to reserve
 #  here a 5MiB memory region.
 #  Notice that we assume ramoops is a module here - if built-in, we should