build-unit-test-docker: Fix home dir creation

`adduser` does not recursively create home directories. If the current
user has a non-standard home directory the command will fail and the
unit test builder will error out. Lets make sure the parent directory
for the home is created first.

Change-Id: Id1cfae38b0bae445e27a1916962cd22ff0863a86
Signed-off-by: William A. Kennington III <wak@google.com>
1 file changed