modem-manager: uninhibit modem after upgrade
modem-manager: uninhibit modem after upgrade

When fastboot is used, the modem is rediscovered through udev
after upgrading. However, the modem-manager plugin did not mark
the modem as unhibited with ModemManager. This resulted into
ModemManager not exposing the modem without restarting ModemManager or
rebooting the device.

Mark the modem as uninhibited and do not take ownership over the
plugin data as this caused segfaults.

fwupd/fwupd,fwupd/fwupd,fwupd/fwupd,fwupd/fwupd