Steps to reproduce
------------------

  * Get a machine with 2 network devices
  * Connect both of the NICs to get such routes:

> # ip route show
> default via 192.168.2.1 dev enp0s25 proto static metric 100 
> default via 192.168.1.254 dev wlp3s0 proto static metric 600 
> 192.168.1.0/24 dev wlp3s0 proto kernel scope link src 192.168.1.131 metric 600 
> 192.168.2.0/24 dev enp0s25 proto kernel scope link src 192.168.2.2 metric 100 

  * Run dracut --force

Actual Results
--------------

The dracut log shows these sort of error messages:

> Failed to look up reference node - returned empty list
> sed: can't read /etc/install.inf: No such file or directory
> sed: -e expression #1, char 13: unterminated address regex
> Failed to look up reference node - returned empty list
> /lib/kdump/setup-kdump.functions: line 468: /sys/class/net/enp0s25
> wlp3s0/addr_assign_type: No such file or directory
> /lib/kdump/setup-kdump.functions: line 469: [: : integer expression expected
> Cannot read permanent address: No such device
> Failed to look up reference node - returned empty list
> sed: can't read /etc/install.inf: No such file or directory
> sed: -e expression #1, char 13: unterminated address regex
> Failed to look up reference node - returned empty list
> /lib/kdump/setup-kdump.functions: line 468: /sys/class/net/enp0s25
> wlp3s0/addr_assign_type: No such file or directory
> /lib/kdump/setup-kdump.functions: line 469: [: : integer expression expected
> Cannot read permanent address: No such device

Problem analysis
----------------

The function kdump_default_netdev in /lib/kdump/setup-kdump.functions doesn't handle the case where several default routes are existing. Using the metric to get one default device (or pick the first one if all with the same metric), could fix the problem.