VOL-1460 Updated core to use voltha-protos instead of local protos
Moved protos to python directory in order to maintain functionaly of containers built there.
Added capability to do local builds of protos
Added instructions on running dep ensure for getting protos.
Updated github.com/golang/protobuf version to v1.3.1

Change-Id: Ia6ef55f07f0d5dcb5b750d7c37b21b71db85bfc4
diff --git a/python/protos/health.proto b/python/protos/health.proto
new file mode 100644
index 0000000..907b683
--- /dev/null
+++ b/python/protos/health.proto
@@ -0,0 +1,36 @@
+syntax = "proto3";
+
+option go_package = "github.com/opencord/voltha-protos/go/voltha";
+
+package voltha;
+
+import "google/api/annotations.proto";
+import "google/protobuf/empty.proto";
+import "meta.proto";
+
+// Encode health status of a Voltha instance
+message HealthStatus {
+
+    // Health states
+    enum HealthState {
+        HEALTHY = 0;  // The instance is healthy
+        OVERLOADED = 1;  // The instance is overloaded, decrease query rate
+        DYING = 2;  // The instance is in a critical condition, do not use it
+    }
+
+    // Current state of health of this Voltha instance
+    HealthState state = 1 [(access) = READ_ONLY];
+}
+
+// Health related services
+service HealthService {
+
+    // Return current health status of a Voltha instance
+    rpc GetHealthStatus(google.protobuf.Empty) returns (HealthStatus) {
+        option (google.api.http) = {
+            get: "/health"
+        };
+    }
+
+}
+