Switch initrd compression to gzip
Switch initrd compression to gzip

Decompressing the gzip compressed initial ramdisk during boot takes only 1.5 seconds compared  to approx. 15 seconds with lzma. Drawback is an increased size of the image of about 25-30 MB,
rancher/os,rancherio/os,rancher/os,ibuildthecloud/os,rancherio/os,rancherio/os,ibuildthecloud/os