Merge "Document mkdir behavioural change"

mkdir <path> [mode] [owner] [group]

   Create a directory at <path>, optionally with the given mode, owner, and

   group. If not provided, the directory is created with permissions 755 and

   owned by the root user and root group.

   owned by the root user and root group. If provided, the mode, owner and group

   will be updated if the directory exists already.

mount <type> <device> <dir> [ <flag> ]* [<options>]

   Attempt to mount the named device at the directory <dir>