treewide: fix previously disabled shellcheck warnings

...n-alfred/files/usr/lib/autoupdater/abort.d/60gluon-alfred

...lfred/files/usr/lib/autoupdater/download.d/40gluon-alfred

...ter/files/usr/lib/autoupdater/abort.d/90gluon-autoupdater

.../files/usr/lib/autoupdater/download.d/10gluon-autoupdater

package/gluon-core/files/lib/gluon/label_mac.sh

package/gluon-core/files/lib/netifd/proto/gluon_mesh.sh

package/gluon-core/files/lib/netifd/proto/gluon_wired.sh

...arp/files/usr/lib/autoupdater/abort.d/15start-arp-limiter

...rp/files/usr/lib/autoupdater/upgrade.d/05stop-arp-limiter

...luon-mesh-batman-adv/files/lib/netifd/proto/gluon_bat0.sh

...man-adv/files/usr/lib/autoupdater/abort.d/10start-network

...an-adv/files/usr/lib/autoupdater/upgrade.d/10stop-network

...luon-mesh-olsrd/files/usr/lib/autoupdater/abort.d/10olsrd

...on-mesh-olsrd/files/usr/lib/autoupdater/upgrade.d/10olsrd

...pn-wireguard/files/lib/gluon/mesh-vpn/wireguard_pubkey.sh

...h-vpn-wireguard/files/lib/netifd/proto/gluon_wireguard.sh

...uon-radvd/files/usr/lib/autoupdater/abort.d/80gluon-radvd

...-radvd/files/usr/lib/autoupdater/download.d/20gluon-radvd

...spondd/files/usr/lib/autoupdater/abort.d/50gluon-respondd

...ndd/files/usr/lib/autoupdater/download.d/50gluon-respondd