coova-chilli: Fix removal of old files

coova-chilli: Fix removal of old files

Before starting chilli instance, it first removes generated
files (/var/run/chilli*) for the instance. While deleting
generated files, it doesn't match full instance name.

Thus if coova-chilli config file (/etc/config/chilli) has
instances wlan11 and wlan1 in order,
when creating coova-chilli instance for wlan1, it is removing
files generated for wlan11 instances also (as it uses wlan1*
in remove command).

Fix issue by matching full instance name while removing old files.

Signed-off-by: Rajan Vaja <redacted>
Signed-off-by: Bhargav Patel <redacted>