command: Fix the command package test build

Some merging conflict shenanigans here led to this usage not lining up
with the imported symbol name, meaning that the tests couldn't compile any
more.

command/command_test.go

@@ -713,7 +713,7 @@ func testBackendState(t *testing.T, s *terraform.State, c int) (*terraform.State
 		Type:   "http",
 		Config: configs.SynthBody("<testBackendState>", map[string]cty.Value{}),
 	}
-	b := backendinit.Backend("http")()
+	b := backendInit.Backend("http")()
 	configSchema := b.ConfigSchema()
 	hash := backendConfig.Hash(configSchema)