dotcloud/docker — pull request #6669 by pwaller (2014-06-25 08:24:19+00:00)
Title: Allow re-mounting an existing mount with "remount"

Without this line of code, if a volume is present in /proc/mounts, it cannot
be remounted with new mount options.

Docker-DCO-1.1-Signed-off-by: Peter Waller (github: pwaller)

Fix #6652

Tested to the extent that I see the syscall through strace with `remount`
and this new code but not without.