main/busybox: Fix resolv.conf update in udhcpc default.script

udhcpc updates /etc/resolv.conf by default (unless disabled by setting "RESOLV_CONF=no" in /etc/udhcpc/udhcpc.conf).

The update is performed in the default script by writing to a temporary resolv.conf file, which is then moved to /etc/resolv.conf via "mv". That "mv" operation may become interactive, prompting "mv: overwrite '/etc/resolv.conf'?", for example when /etc/resolv.conf is marked immutable (chattr +i)

Since udhcpc is usually called during unattended boot, this may block the device.

Change "mv" to "mv -f", which will not block (but may still fail to update the file when /etc/resolv.conf is immutable).

Signed-off-by: Christian Kohlschütter christian@kohlschutter.com

(posted from https://lists.alpinelinux.org/~alpine/devel/%3CB923B294-DC86-47DF-B34D-107059863AFE%40kohlschutter.com%3E)