Retire LOCAL_NDK_VERSION.
Retire LOCAL_NDK_VERSION.

Bug: 6932421
Change-Id: I4007da47dcff1ab582598507c4a5f092c48bb1cd

xin3liang/platform_external_srtp,geekboxzone/lollipop_external_srtp,geekboxzone/mmallow_external_srtp,CyanogenMod/android_external_srtp,IllusionRom-deprecated/android_platform_external_srtp,geekboxzone/mmallow_external_srtp,yinquan529/platform-external-srtp,CyanogenMod/android_external_srtp,omapzoom/platform-external-srtp,IllusionRom-deprecated/android_platform_external_srtp,Omegaphora/external_srtp,omapzoom/platform-external-srtp,geekboxzone/lollipop_external_srtp,geekboxzone/lollipop_external_srtp,android-ia/platform_external_srtp,Omegaphora/external_srtp,xin3liang/platform_external_srtp,android-ia/platform_external_srtp,geekboxzone/mmallow_external_srtp,IllusionRom-deprecated/android_platform_external_srtp,yinquan529/platform-external-srtp