adb: don't explode directories when pushing/pulling.

Previously, `adb pull /data/local/tmp` would spew all of the contents of
/data/local/tmp into the current directory. This patch makes push/pull
keep directories intact.

Bug: http://b/25394682
Change-Id: I2304ae9e61745a2b9536f58a6012640bf8ff422a
2 files changed