Enable contractWatcher without prior headerSync

- Previous setup would fail if there were no headers in the db. This
  makes sense because we need headers that haven't been checked for
  logs to exist so that we can fetch logs for those headers. But it
  also prevents us from kicking off the headerSync and contractWatcher
  processes concurrently. These changes enable kicking off both
  processes at the same time with the idea that we will have unchecked
  headers upon transformer execution.

integration_test/contract_watcher_header_sync_transformer_test.go

@@ -78,11 +78,10 @@ var _ = Describe("contractWatcher headerSync transformer", func() {
 			Expect(c.Address).To(Equal(tusdAddr))
 		})
 
-		It("Fails to initialize if first and block cannot be fetched from vDB headers table", func() {
+		It("initializes when no headers available in db", func() {
 			t := transformer.NewTransformer(test_helpers.TusdConfig, blockChain, db)
 			err = t.Init()
-			Expect(err).To(HaveOccurred())
-			Expect(err.Error()).To(ContainSubstring("no rows in result set"))
+			Expect(err).ToNot(HaveOccurred())
 		})
 
 		It("Does nothing if nothing if no addresses are configured", func() {