Depending on bootloader and configuration, ramdisks may receive
a ip= kernel parameter that is used for manual network bring up
in the ramdisk. This parameter contains the address of the boot
server. In the absence of ip=, we want the ramdisk to DHCP and
proceed as normal. However, in this case need to know the address
of the boot server. This falls back to a 'boot_server' parameter
for this address if it is not provided via kernel cmdline.
Change-Id: Id1ed15ba125d91fa0a13d8e19d1385082ee5d9e9
Closes-bug: #1401289
Related-bug: #1401298
441b30f89f