support 'enableTagOverride' for consul backend

[difro]

consul 0.6 landed with 'enableTagOverride' which disables 'anti-entropy' feature for each service being registered. This lets external agents to modify tags for already registered services.

Since this has been merged into consul go api,
It'd be great registrator also supported this feature.

I'm thinking maybe, something like SERVER_ENABLETAGOVERRIDE=true env ?

[thefab]

+1, required to properly deal with master/slave status on services (the master/slave tag is set after a leader election)

[difro]

I'm thinking maybe it'd be ok even if 'enableTagOverride' was always set to true.

Should be a 1~2 line PR. Will cook one up soon.

[thutcheson-jha]

+1

[bitsofinfo]

+1

[bmudda]

+1

[kkonstantin42]

+1

[phuslu]

+1