Remove DCO check from makefile, move to .travis.yml

The DCO check is primarily only relevant as part of CI, so it
doesn't need to be in the Makefile. A contributor looking to
validate their commits can run script/validate/dco.

Signed-off-by: Daniel Nephin <dnephin@gmail.com>

.travis.yml

@@ -51,7 +51,7 @@ install:
 script:
   - export GOOS=$TRAVIS_GOOS
   - export CGO_ENABLED=$TRAVIS_CGO_ENABLED
-  - GIT_CHECK_EXCLUDE="./vendor" TRAVIS_COMMIT_RANGE="${TRAVIS_COMMIT_RANGE/.../..}" make dco
+  - DCO_VERBOSITY=-q script/validate/dco
   - GOOS=linux script/setup/install-dev-tools
   - go build -i .
   - make check

Makefile

@@ -65,7 +65,7 @@ endif
 TESTFLAGS ?= -v $(TESTFLAGS_RACE)
 TESTFLAGS_PARALLEL ?= 8
 
-.PHONY: clean all AUTHORS fmt vet lint dco build binaries test integration generate protos checkprotos coverage ci check help install uninstall vendor release
+.PHONY: clean all AUTHORS build binaries test integration generate protos checkprotos coverage ci check help install uninstall vendor release
 .DEFAULT: default
 
 all: binaries
@@ -106,14 +106,6 @@ proto-fmt: ## check format of proto files
 	@test -z "$$(find . -path ./vendor -prune -o -name '*.proto' -type f -exec grep -Hn "Meta meta = " {} \; | grep -v '(gogoproto.nullable) = false' | tee /dev/stderr)" || \
 		(echo "$(ONI) meta fields in proto files must have option (gogoproto.nullable) = false" && false)
 
-dco: ## dco check
-	@which git-validation > /dev/null 2>/dev/null || (echo "ERROR: git-validation not found" && false)
-ifdef TRAVIS_COMMIT_RANGE
-	git-validation -q -run DCO,short-subject,dangling-whitespace
-else
-	git-validation -v -run DCO,short-subject,dangling-whitespace -range $(EPOCH_TEST_COMMIT)..HEAD
-endif
-
 build: ## build the go packages
 	@echo "$(WHALE) $@"
 	@go build ${GO_BUILD_FLAGS} ${EXTRA_FLAGS} ${GO_LDFLAGS} ${GO_GCFLAGS} ${PACKAGES}

script/validate/dco

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -eu -o pipefail
+
+if ! command -v git-validation; then
+    >&2 echo "ERROR: git-validation not found. Install with:"
+    >&2 echo "    go get -u github.com/vbatts/git-validation"
+    exit 1
+fi
+
+GIT_CHECK_EXCLUDE="./vendor"
+verbosity="${DCO_VERBOSITY--v}"
+git-validation "$verbosity" -run DCO,short-subject,dangling-whitespace