Return path including executable instead of without

The previous implementation returned the path the executable was in instead
of returning the path including the executable (i.e. it returned ...bin
instead of ...bin/executable). This is not what the original methods did
and caused the process forking of adb to fail.

This patch corrects the implementation.

(cherry picked from commit 26b53bb7)

Change-Id: Icad6870bbb0a88f611ca71d90fff30f7b576c367