updatedeps should checkout the last checked out branch [GH-816]

Makefile

@@ -22,8 +22,14 @@ testrace: generate
 	TF_ACC= go test -race $(TEST) $(TESTARGS)
 
 updatedeps:
+	@# This just checks out the current branch/tag/commit again so
+	@# that the `git checkout -` works below. We do this to preserve our
+	@# location since `go get` always puts us back on the master branch.
+	@sh -c "git checkout `git symbolic-ref --short HEAD 2>/dev/null \
+		|| git rev-parse HEAD`"
 	go get -u golang.org/x/tools/cmd/stringer
 	go get -f -u -v ./...
+	git checkout -
 
 generate:
 	go generate ./...