McdStorage: delete_cb: improve clarity with a temporary variable
McdStorage: delete_cb: improve clarity with a temporary variable

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=27727

freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control