Using the pattern `^GRUB_CMDLINE_LINUX` both `GRUB_CMDLINE_LINUX` and
`GRUB_CMDLINE_LINUX_DEFAULT`options are matching, however only
`GRUB_CMDLINE_LINUX` intented to be configured.
Change-Id: Iae564f5a97694d036c450f0535ec7b4705d506b7 Signed-off-by: Krisztian Lengyel <krisztian.lengyel@nokia.com>