linux_udev: Initialize pointer before calling external API
udev_list_entry_foreach() sets the entry variable for each device but
initializing the pointer to NULL to avoid warnings.
Found by Coverity:
libusb-1.0.21/libusb/os/linux_udev.c:273:
error[uninitvar]: Uninitialized variable: entry
> 271| devices = udev_enumerate_get_list_entry(enumerator);
> 272|
> 273|-> udev_list_entry_foreach(entry, devices) {
> 274| const char *path = udev_list_entry_get_name(entry);
> 275| uint8_t busnum = 0, devaddr = 0;
Signed-off-by: Victor Toso <victortoso@redhat.com>
Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>