Configure: moved icc detection before gcc.

New versions of icc confuse auto/cc/name due to introduced handling
of a "icc -v":

$ icc -v
icc version 12.1.3 (gcc version 4.6.0 compatibility)
$ icc -V
Intel(R) C Compiler XE for applications running on IA-32, Version 12.1.3.293 Build 20120212
Copyright (C) 1985-2012 Intel Corporation.  All rights reserved.
FOR NON-COMMERCIAL USE ONLY

See report here:
http://mailman.nginx.org/pipermail/nginx/2012-February/032177.html

auto/cc/name

@@ -63,16 +63,16 @@ if [ "$CC" = bcc32 ]; then
     NGX_CC_NAME=bcc
     echo " + using Borland C++ compiler"
 
-else
-if `$CC -v 2>&1 | grep 'gcc version' >/dev/null 2>&1`; then
-    NGX_CC_NAME=gcc
-    echo " + using GNU C compiler"
-
 else
 if `$CC -V 2>&1 | grep '^Intel(R) C' >/dev/null 2>&1`; then
     NGX_CC_NAME=icc
     echo " + using Intel C++ compiler"
 
+else
+if `$CC -v 2>&1 | grep 'gcc version' >/dev/null 2>&1`; then
+    NGX_CC_NAME=gcc
+    echo " + using GNU C compiler"
+
 else
 if `$CC -V 2>&1 | grep 'Sun C' >/dev/null 2>&1`; then
     NGX_CC_NAME=sunc