Use PlatformSdkVersion from Make

This doesn't need to be hardcoded, and should be updated anyways.

Change-Id: Ie28d0d7655e8db3c02d110ae578a763a69b73f92
diff --git a/android/config.go b/android/config.go
index 0f65410..ae04756 100644
--- a/android/config.go
+++ b/android/config.go
@@ -20,6 +20,7 @@
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -278,7 +279,7 @@
 }
 
 func (c *config) PlatformSdkVersion() string {
-	return "22"
+	return strconv.Itoa(*c.ProductVariables.Platform_sdk_version)
 }
 
 func (c *config) BuildNumber() string {