Remove addKeyFromFile() method
Remove addKeyFromFile() method

Prompted by a pylint E1123 (unexpected-keyword-arg) message, but this method
seems both unused and broken.

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

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