Remove vpn from FRAMEWORKS_BASE_SUBDIRS
Remove vpn from FRAMEWORKS_BASE_SUBDIRS

To eliminate build warning.
Reference commit: 44e27b5c74b5f441973561a4f945cb58e0cc45a4
which removed framework/base/vpn.

Change-Id: I539e4bc2a4008c8b9eed74dd53eec1f55db3abe5

fallouttester/platform_manifest,xorware/android_build,pranav01/platform_manifest,ND-3500/platform_manifest,xorware/android_build,see4ri/lolili,xorware/android_build,knone1/platform_manifest,xorware/android_build,hagar006/platform_manifest,RR-msm7x30/platform_manifest,xorware/android_build,Hybrid-Power/startsync