CA-142533: Don't keep fd open for /dev/vga_arbiter

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #1918 from simonjbeaumont/ca-142533

CA-142533: Don't keep fd open for /dev/vga_arbiter
Update cli_frontend.ml

fix documentation for vif- and vdi mappings
Merge pull request #1922 from zaiyers/master

Update cli_frontend.ml
Release 1.9.53

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #1923 from djs55/release-1.9.53

Release 1.9.53