Use ctx.Fatalln instead of log.Fatalln for absolute path errors

log.Fatalln calls os.Exit, which skips deferred functions and
leaves the console with the cursor disabled.  Use ctx.Fatalln
instead, which uses a panic to exit and calls the deferred
function to restore the cursor.

Test: DIST_DIR=/tmp/\test\ foo m dist
Change-Id: Ie92297075e37c171d5ba48848a0ddb19652b051c