Upstream: simplified some code that accesses peers.

No functional changes.
Updated OpenSSL used for win32 builds.
Configure: workaround for system perl on OS X (ticket #576).
nginx-1.7.2-RELEASE
release-1.7.2 tag
Core: added ngx_slab_calloc() and ngx_slab_calloc_locked().

These functions return zeroed memory, analogous to ngx_pcalloc().
FreeBSD has migrated to Bugzilla.
Upstream: reduced diffs to the plus version of nginx.

No functional changes.
Not modified filter: debug log format fixed.
Upstream: no need to clear r->headers_out.last_modified_time.

Clearing of the r->headers_out.last_modified_time field if a response
isn't cacheable in ngx_http_upstream_send_response() was introduced
in 3b6afa999c2f, the commit to enable not modified filter for cacheable
responses.  It doesn't make sense though, as at this point header was
already sent, and not modified filter was already executed.  Therefore,
the line was removed to simplify code.