make check not self-consistent

[dgrell]

In r574, one test in make check looks for the libs in --prefix rather than using the pre-install build location:

# TOTAL: 17
# PASS:  16
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: test-yoda-1.py
====================

Traceback (most recent call last):
  File "./test-yoda-1.py", line 3, in <module>
    import yoda
  File "/Users/dg/src/YODA/pyext/build/yoda/__init__.py", line 1, in <module>
    from yoda.core import *
ImportError: dlopen(/Users/dg/src/YODA/pyext/build/yoda/core.so, 2): Library not loaded: /Users/dg/opt/YODA/lib/libYODA.0.dylib
  Referenced from: /Users/dg/src/YODA/pyext/build/yoda/core.so
  Reason: image not found