this fixes OpenSSL "bad write retry" error, when
*) nginx passed a single buf greater than our buffer (say 32K) to OpenSSL,
*) OpenSSL returns SSL_ERROR_WANT_WRITE,
*) after some time nginx has to send a new data,
*) so there are at least two bufs nginx does pass them directly to OpenSSL,
*) but copies the first buf part to buffer, and sends the buffer to OpenSSL.
*) because the data length is lesser than it was in previous SSL_write():
   16K < 32K, OpenSSL returns SSL_R_BAD_WRITE_RETRY.

*) allow address without bitmask
*) thus now ngx_http_geo_module accepts addresses without bitmask

broken in r2128

this fixes mail proxy SSL connection hanging if level-triggered event is used

*) test ssl_client_certificate for ssl_verify_client
*) $ssl_client_cert adds TAB before each line except first one
*) $ssl_client_raw_cert contains certificate as is