devel/android-tools-{adb,fastboot}: update to 6.0.0.r26

Changes: https://android.googlesource.com/platform/system/core/+log/android-6.0.0_r1..android-6.0.0_r26/adb (device only)
Changes: https://android.googlesource.com/platform/system/core/+log/android-6.0.0_r1..android-6.0.0_r26/fastboot