RPATH is being incorrectly overwritten

[ehashman]

As originally reported by @thomaslima:

Our wheel has a complicated dependency structure. But the gist of it is the following:

dbcore.so (py_ext) -> lib_tl.so (non-py_ext) -> libcurl.so (external library to be grafted)

dbcore already had an RPATH set to $ORIGIN. So because of its dependency to libcurl.so, patchelf_set_rpath replaced it to $ORIGIN/.libs in repair.py, even though it was not necessary. This way, it could no longer find lib_tl.so.

See also #134.