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 c2059edce2 ("elf: Use
_dl_catch_error from base namespace in dl-libc.c [BZ #27646]") and
commit b2964eb1d9 ("dlfcn: Failures
after dlmopen should not terminate process [BZ #24772]").

elf/dl-libc.c

@@ -48,7 +48,7 @@ dlerror_run (void (*operate) (void *), void *args)
 		?: last_errstring != NULL);
 
   if (result && malloced)
-    free ((char *) last_errstring);
+    GLRO (dl_error_free) ((char *) last_errstring);
 
   return result;
 }