Remove an OpenBSD note in the README which is no longer necessary.

OpenBSD's behavior has not changed, but the default SBCL allocation
size was changed some time ago to work with the default OpenBSD
resource limits.

Author: jre

README

@@ -33,15 +33,3 @@ SYSTEM-SPECIFIC HINTS
 for NetBSD:
   NetBSD 2.0 and above are required because of the lack of needed
   signal APIs in NetBSD 1.6 and earlier.
-
-for OpenBSD:
-  OpenBSD 3.0 has stricter ulimit values, and/or enforces them more
-  strictly, than its predecessors. Therefore SBCL's initial mmap()
-  won't work unless you increase the limit on the data segment from
-  the OpenBSD defaults, e.g. with
-    ulimit -S -d 1000000
-  before you run SBCL. Otherwise SBCL fails with a message like
-  "ensure_space: failed to validate xxxxxxx bytes at yyyyy". (SBCL
-  is just allocating this huge address space, not actually using this
-  huge memory at this point. OpenBSD <3.0 had no problem with this,
-  but OpenBSD 3.0 is less hospitable.)