Sync up Agent and API's renewers. (#7733)

* Sync up Agent and API's renewers.

This introduces a new type, LifetimeWatcher, which can handle both
renewable and non-renewable secrets, modeled after the version in Agent.
It allows the user to select behavior, with the new style being the
default when calling Start(), and old style if using the legacy Renew()
call.

No tests have been modified (except for reflect issues) and no other
code has been modified to make sure the changes are backwards
compatible.

Once this is accepted I'll pull the Agent version out.

* Move compat flags to NewRenewer

* Port agent to shared lifetime watcher lib

api/go.mod

@@ -5,6 +5,7 @@ go 1.12
 replace github.com/hashicorp/vault/sdk => ../sdk
 
 require (
+	github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31
 	github.com/hashicorp/errwrap v1.0.0
 	github.com/hashicorp/go-cleanhttp v0.5.1
 	github.com/hashicorp/go-multierror v1.0.0

api/go.sum

@@ -10,6 +10,7 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
 github.com/go-ldap/ldap v3.0.2+incompatible/go.mod h1:qfd9rJvER9Q0/D/Sqn1DfHRoBp40uXYvFoEVrNEPqRc=
+github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31 h1:28FVBuwkwowZMjbA7M0wXsI6t3PYulRTMio3SO+eKCM=
 github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
@@ -37,7 +38,6 @@ github.com/hashicorp/go-rootcerts v1.0.1/go.mod h1:pqUvnprVnM5bf7AOirdbb01K4ccR3
 github.com/hashicorp/go-sockaddr v1.0.2 h1:ztczhD1jLxIRjVejw8gFomI1BQZOe2WoVOu0SyteCQc=
 github.com/hashicorp/go-sockaddr v1.0.2/go.mod h1:rB4wwRAUzs07qva3c5SdrY/NEtAUjGlgmH/UkBUC97A=
 github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
-github.com/hashicorp/go-uuid v1.0.1/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/go-uuid v1.0.2-0.20191001231223-f32f5fe8d6a8/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/go-version v1.1.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=