lh_chroot_linux-image: Catch missing case in local live-initramfs handling

This patch catches the case when LH_APT is "apt", its default value. This
was causing build failures when using a local live-initramfs .deb.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>

helpers/lh_chroot_linux-image

@@ -98,7 +98,7 @@ EOF
 				aptitude)
 					Apt install ${LH_INITRAMFS}
 					;;
-				apt-get)
+				apt|apt-get)
 					Apt install -f
 					;;
 			esac