[xen-tools] option install is more intuitive than no-install

[Henning Sprang]

Hi,
I just realize, that the option

no-install

is a bit counter-intuitive.

It was introduced to combine xen-tools with other installing tools, like 
fai, to suppress xen-tools install completely (only using the config and 
block device generation facilities).

Now when trying to use it again, I realize, this is not exactly intuitive.

Rather it should be install=0|1, with the default set to 1.

any opinions?

Henning