kdumpst-load: Don't unnecessarily recreate GRUB config on pstore load

What happens here is that the way GRUB's cmdline _removal_ was implemented
so far, it tries to remove "crashkernel=" from GRUB in pstore case, based
on kdumpst configuration. BUT it generates the GRUB config no matter what,
so if users added a crashkernel entry themselves, that doesn't match
kdumpst config file, what happens now is:

1) The code will try to sed-out our crashkernel setting from GRUB's
config, with no success (since our particular setting's not there);

2) GRUB config *will be* recreated by kdumpst (needlessly).

Fix that by checking if our crashkernel tuning is there before
the sed command is attempted (and the GRUB config, recreated).

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

kdumpst-load.sh.in

@@ -26,6 +26,11 @@ grub_update() {
 		fi
 
 		if [ "$1" = "pstore" ] && [ "${CRASHK}" -ne 0 ]; then
+			#  Let's be sure our cmdline is there...
+			if ! grep -q "${GRUB_CMDLINE}" "${GRUB_CFG_FILE}"; then
+				return 0
+			fi
+
 			sed -i "s/\"${GRUB_CMDLINE}/\"/g" "${GRUB_CFG_FILE}"
 
 			if ! grub-mkconfig -o "${GRUB_BOOT_FILE}" 1>/dev/null; then