Add constraints to manifest

- Updated Gopkg.toml manually (NOTE: Using the "revision" constraint is
  not usually recommended, but it was the easiest to do for the moment
  and would ensure consistency with what was previously in the Godeps
  manifest)
- Ran dep ensure && dep prune (dep v0.3.2)

ecs-cli/Gopkg.toml

@@ -23,44 +23,58 @@
 
 [[constraint]]
   name = "github.com/aws/aws-sdk-go"
+  # version = "1.12.58"
+  revision = "ccb909e564ddced884491d966808d9b245a86e6a"
 
 [[constraint]]
   name = "github.com/awslabs/amazon-ecr-credential-helper"
+  revision = "19c5038b3c1fc63328b4eb99c507c72f12a27f66"
 
 [[constraint]]
   name = "github.com/cihub/seelog"
+  revision = "a98235bd6d927ba8379ef4f0050c32c9a2ea17b8"
 
 [[constraint]]
   name = "github.com/docker/go-units"
+  revision = "e30f1e79f3cd72542f2026ceec18d3bd67ab859c"
 
 [[constraint]]
   name = "github.com/docker/libcompose"
+  revision = "57bd716502dcbe1799f026148016022b0f3b989c"
 
 [[constraint]]
-  branch = "master"
   name = "github.com/flynn/go-shlex"
+  revision = "3f9db97f856818214da2e1057f8ad84803971cff"
 
 [[constraint]]
   name = "github.com/fsouza/go-dockerclient"
+  revision = "4a934a8fd3ec3d4f84d9dcd8b47e7b277918c366"
 
 [[constraint]]
   name = "github.com/go-ini/ini"
+  revision = "32e4c1e6bc4e7d0d8451aa6b75200d19e37a536a"
 
 [[constraint]]
   name = "github.com/golang/mock"
+  revision = "bd3c8e81be01eef76d4b503f5e687d2d1354d2d9"
 
 [[constraint]]
   name = "github.com/pkg/errors"
+  revision = "248dadf4e9068a0b3e79f02ed0a610d935de5302"
 
 [[constraint]]
   name = "github.com/sirupsen/logrus"
   version = "1.0.4"
 
 [[constraint]]
   name = "github.com/stretchr/testify"
+  revision = "2402e8e7a02fc811447d11f881aa9746cdc57983"
 
 [[constraint]]
   name = "github.com/urfave/cli"
+  # version = "1.19.1"
+  revision = "2526b57c56f30b50466c96c4133b1a4ad0f0191f"
 
 [[constraint]]
   name = "gopkg.in/yaml.v2"
+  revision = "a5b47d31c556af34a302ce5d659e6fea44d90de0"