Cleans up vendor metadata. (#2507)

* Removes bad "context" dep.

* Updates Raft checksum.

* Cleans up go-msgpack vendoring.

* Cleans up EC2 vendor entry.

vendor/vendor.json

@@ -2,10 +2,6 @@
 	"comment": "",
 	"ignore": "test",
 	"package": [
-		{
-			"path": "context",
-			"revision": ""
-		},
 		{
 			"checksumSHA1": "JhyS/zIicgtrSasHSZ6WtXGWJVk=",
 			"path": "github.com/DataDog/datadog-go/statsd",
@@ -48,12 +44,6 @@
 			"revision": "4239b77079c7b5d1243b7b4736304ce8ddb6f0f2",
 			"revisionTime": "2016-01-15T23:47:25Z"
 		},
-		{
-			"checksumSHA1": "cFpKkRqSacWTuz24u7i4K8xy/hA=",
-			"path": "github.com/aws/aws-sdk-go//service/ec2",
-			"revision": "ed981a1d5ee78d20547091d0697a711e5185d07f",
-			"revisionTime": "2016-10-31T21:52:18Z"
-		},
 		{
 			"checksumSHA1": "NeKH+twA+3z7EzaKQQdN5FIhJP4=",
 			"path": "github.com/aws/aws-sdk-go/aws",
@@ -192,6 +182,12 @@
 			"revision": "ed981a1d5ee78d20547091d0697a711e5185d07f",
 			"revisionTime": "2016-10-31T21:52:18Z"
 		},
+		{
+			"checksumSHA1": "6h4tJ9wVtbYb9wG4srtUxyPoAYM=",
+			"path": "github.com/aws/aws-sdk-go/service/ec2",
+			"revision": "ed981a1d5ee78d20547091d0697a711e5185d07f",
+			"revisionTime": "2016-10-31T21:52:18Z"
+		},
 		{
 			"checksumSHA1": "ouwhxcAsIYQ6oJbMRdLW/Ys/iyg=",
 			"path": "github.com/aws/aws-sdk-go/service/sts",
@@ -382,8 +378,10 @@
 			"revisionTime": "2016-03-01T23:01:42Z"
 		},
 		{
+			"checksumSHA1": "TNlVzNR1OaajcNi3CbQ3bGbaLGU=",
 			"path": "github.com/hashicorp/go-msgpack/codec",
-			"revision": "fa3f63826f7c23912c15263591e65d54d080b458"
+			"revision": "fa3f63826f7c23912c15263591e65d54d080b458",
+			"revisionTime": "2015-05-18T23:42:57Z"
 		},
 		{
 			"checksumSHA1": "lrSl49G23l6NhfilxPM0XFs5rZo=",
@@ -506,7 +504,7 @@
 			"revisionTime": "2015-11-16T02:03:38Z"
 		},
 		{
-			"checksumSHA1": "hwvKyyRujRkxMtrdwigHuE5SIyo=",
+			"checksumSHA1": "wpirHJV/6VEbbD+HyAP2/6Xc0ek=",
 			"path": "github.com/hashicorp/raft",
 			"revision": "aaad9f10266e089bd401e7a6487651a69275641b",
 			"revisionTime": "2016-11-10T00:52:40Z"