Proxy: improved code readability.

Do not assume that space character follows the method name, just pass it
explicitly.

The fuss around it has already proved to be unsafe, see bbdb172f0927 and
http://mailman.nginx.org/pipermail/nginx-ru/2013-January/049692.html for
details.

src/http/modules/ngx_http_proxy_module.c

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index e9224e2..a869e74 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1157,25 +1157,24 @@
     if (u->method.len) {
         /* HEAD was changed to GET to cache response */
         method = u->method;
-        method.len++;
 
     } else if (plcf->method.len) {
         method = plcf->method;
 
     } else {
         method = r->method_name;
-        method.len++;
     }
 
     ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);
 
-    if (method.len == 5
-        && ngx_strncasecmp(method.data, (u_char *) "HEAD ", 5) == 0)
+    if (method.len == 4
+        && ngx_strncasecmp(method.data, (u_char *) "HEAD", 4) == 0)
     {
         ctx->head = 1;
     }
 
-    len = method.len + sizeof(ngx_http_proxy_version) - 1 + sizeof(CRLF) - 1;
+    len = method.len + 1 + sizeof(ngx_http_proxy_version) - 1
+          + sizeof(CRLF) - 1;
 
     escape = 0;
     loc_len = 0;
@@ -1294,6 +1293,7 @@
     /* the request line */
 
     b->last = ngx_copy(b->last, method.data, method.len);
+    *b->last++ = ' ';
 
     u->uri.data = b->last;
 
@@ -3159,13 +3159,6 @@
 
     ngx_conf_merge_str_value(conf->method, prev->method, "");
 
-    if (conf->method.len
-        && conf->method.data[conf->method.len - 1] != ' ')
-    {
-        conf->method.data[conf->method.len] = ' ';
-        conf->method.len++;
-    }
-
     ngx_conf_merge_value(conf->upstream.pass_request_headers,
                               prev->upstream.pass_request_headers, 1);
     ngx_conf_merge_value(conf->upstream.pass_request_body,