Explicitly accept a string as well as a RAIDLevel object.
Explicitly accept a string as well as a RAIDLevel object.

This aligns this choice with the equivalent for mdraid.mdcreate.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

dwlehman/blivet,vojtechtrefny/blivet,AdamWill/blivet,vpodzime/blivet,vojtechtrefny/blivet,rhinstaller/blivet,dwlehman/blivet,rvykydal/blivet,rvykydal/blivet,AdamWill/blivet,vpodzime/blivet,jkonecny12/blivet,jkonecny12/blivet,rhinstaller/blivet