Update functions that return error to not return pointer

* Matches Golang convention

pkg/config/config_test.go

@@ -3,7 +3,7 @@ package config_test
 import (
 	"path/filepath"
 
-	"github.com/8thlight/vulcanizedb/pkg/config"
+	cfg "github.com/8thlight/vulcanizedb/pkg/config"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
@@ -11,20 +11,20 @@ import (
 var _ = Describe("Loading the config", func() {
 
 	It("reads the private config using the environment", func() {
-		privateConfig, err := config.NewConfig("private")
+		privateConfig, err := cfg.NewConfig("private")
 
 		Expect(err).To(BeNil())
 		Expect(privateConfig.Database.Hostname).To(Equal("localhost"))
 		Expect(privateConfig.Database.Name).To(Equal("vulcanize_private"))
 		Expect(privateConfig.Database.Port).To(Equal(5432))
-		expandedPath := filepath.Join(config.ProjectRoot(), "test_data_dir/geth.ipc")
+		expandedPath := filepath.Join(cfg.ProjectRoot(), "test_data_dir/geth.ipc")
 		Expect(privateConfig.Client.IPCPath).To(Equal(expandedPath))
 	})
 
 	It("returns an error when there is no matching config file", func() {
-		config, err := config.NewConfig("bad-config")
+		config, err := cfg.NewConfig("bad-config")
 
-		Expect(config).To(BeNil())
+		Expect(config).To(Equal(cfg.Config{}))
 		Expect(err).NotTo(BeNil())
 	})