Fix double fsck of the root filesystem

It seems this commit was completely left out of 0.8.12, although it was
documented in NEWS.

References: bnc#875738
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Implement kdump_ip_config: get IP configuration options

The code is taken from mkinitrd's setup-network.sh and slightly
improved.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Implement kdump_default_netdev: get the default interface name

This is a modification of "default" interface resolution from mkinitrd.
Differences:

1. Current configuration has precedence over install.inf

   Rationale: If the admin changes the default interface after
   installation, kdump should use the new interface, not the one which
   was configured when the system was first set up.
   In fact, I strongly believe that inisting on the original interface
   has a great potential to cause great frustration.

2. BOOTPROTO=nfsroot has no special meaning

   Rationale: In the normal case, mkinitrd is used to mount the root
   filesystem, so it naturally prefers an interface that is marked as
   needed for the root filesystem. But the root filesystem has no
   special importance for kdump.

3. Mode (dhcp v. static) is first looked up in the configuration

   Rationale: If the DHCP daemon is not running during mkdumprd
   execution, it does not automatically mean that the admin wants
   to configure that interface statically. The admin intention is
   more reliably found in the config files.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Store current configuration if KDUMP_NETCONFIG is static

This improves compatibility with SLES11 kdump. Since dracut misses
some of the required features, the network configuration is resolved
prior to running dracut.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>