Clean: Remove confusing comment from a test

Clean: Remove confusing comment from a test

As per:

  Re: [PATCH 2/2] Clean: Actually use HvUSEDKEYS() instead of HvKEYS()
  Sun, 15 May 2011 20:29:05 +0000
  Message-Id: <2a28ed668b6641e6b5f6e0fb4e5374b4-mfwitten@gmail.com>

the text in question was introduced along with the test in this commit:

  $ c=58da6fbcb8d595318b667d7d7cc8739f5feb15f3
  $ git log -1 $c
  commit 58da6fbcb8d595318b667d7d7cc8739f5feb15f3
  Author: Max Maischein <corion@corion.net>
  Date:   Mon Jun 1 14:18:42 2009 +0200

      Add benchmark test for keys() on empty hashes (RT26188)

I believe the text in question is an allusion to the code introduced in
the parent commit:

  $ git log -1 $c^
  commit 900ac0519e4b408fd93443b14b734cc330c59698
  Author: Max Maischein <corion@corion.net>
  Date:   Sun May 31 23:50:12 2009 +0200

      Fix RT26188, speed up keys() on empty hash

namely the code starting at line 2132 of
900ac0519e4b408fd93443b14b734cc330c59698:hv.c:

   /* At start of hash, entry is NULL.  */
   ...
  if (HvKEYS(hv) || (flags & HV_ITERNEXT_WANTPLACEHOLDERS)) {
      ...
  }
  ...
  return entry;

It is best just to remove the text in question, as it is of no
real use.

Signed-off-by: Michael Witten <mfwitten@gmail.com>