Fix platform specific os/process build

runtime/process/os/process.go

@@ -0,0 +1,12 @@
+// Package os runs processes locally
+package os
+
+import (
+	"github.com/micro/go-micro/runtime/process"
+)
+
+type Process struct{}
+
+func NewProcess(opts ...process.Option) process.Process {
+	return &Process{}
+}