Use module_current for AOSP NetworkStack

Use module_current instead of module_31 in branches that do not yet have
a prebuilt module_31 SDK.

This change should not be merged into branches that have a prebuilt
module_31 SDK.

Bug: 189581241
Test: m NetworkStack NetworkStackNext
Merged-In: Ia55598123a5d4432464e9d1b1c637e9e0b58dd8e
Change-Id: I0332537809aacc09d93db674ac7836267d0518bd
1 file changed