init-ifupdown: remove wrong sed command

This 'sed' command was used in the past, when DHCP or MANUAL was
configured in the '/etc/network/interfaces' (for cellular). This is no
longer true as we always configure the interface with a custom (manual)
script.

This was breaking the rest of interfaces when configured to use 'dhcp':

iface eth0 inet manual
       umanualc_opts -S -b >/dev/null &

Signed-off-by: Javier Viguera <javier.viguera@digi.com>

meta-digi-dey/recipes-core/init-ifupdown/init-ifupdown_1.0.bbappend

@@ -82,7 +82,6 @@ do_install_append() {
 
 		if [ -n "${CELLULAR_PORT}" ]; then
 			sed -i -e 's/^\([[:blank:]]*\)port/\1port ${CELLULAR_PORT}/g' ${D}${sysconfdir}/network/interfaces
-			sed -i -e 's,dhcp,manual,g' ${D}${sysconfdir}/network/interfaces
 		else
 			sed -i -e '/^[[:blank:]]*port/d' ${D}${sysconfdir}/network/interfaces
 		fi