elf: Call free from base namespace on error in dl-libc.c [BZ #27646]

elf: Call free from base namespace on error in dl-libc.c [BZ #27646]

In dlerror_run, free corresponds to the local malloc in the
namespace, but GLRO (dl_catch_error) uses the malloc from the base
namespace.  elf/tst-dlmopen-gethostbyname triggers this mismatch,
but it does not crash, presumably because of a fastbin deallocation.

Fixes commit c2059edce20c124d1a99f1a94cc52e83b77a917a ("elf: Use
_dl_catch_error from base namespace in dl-libc.c [BZ #27646]") and
commit b2964eb1d9a6b8ab1250e8a881cf406182da5875 ("dlfcn: Failures
after dlmopen should not terminate process [BZ #24772]").