Let xapi start even if Xenctl doesn't work.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Hard-wire host total memory to 16GiB

We need some way to either time-out requests to the default xenopsd
or discover some other way to learn host memory.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Hard-wire host total memory to 16 GiB

(see previous commit)

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
If we fail to find a balloon driver in /sys, assume static max = host total memory

Again, there's probably a better number to use somewhere in /sys.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>