dir: Explicitly 'make all' in src/dir/test

dir: Explicitly 'make all' in src/dir/test

Currently, we 'cd test' and then just run 'make', which makes the
first target specified in the Makefile. On some platforms (FreeBSD),
this results in 'make' trying to build '%.c', which of course we
cannot do, since that's a pattern rule, and so 'make' fails.

To fix this, just 'make all' explicitly, to make the intended targets
in src/dir/test.

Change-Id: Icbbf60c9c163c24fbbed01c754c4f1eefeae6b78
Reviewed-on: https://gerrit.openafs.org/14550
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>