HTTP: return larger than 3 digit response codes too

HTTP 1.1 is clearly specified to only allow three digit response codes,
and libcurl used sscanf("%3d") for that purpose. This made libcurl
support smaller numbers but not larger. It does now, but we will not
make any specific promises nor document this further since it is going
outside of what HTTP is.

Bug: http://curl.haxx.se/bug/view.cgi?id=1441
Reported-by: Balaji

tests/data/test1431

@@ -0,0 +1,53 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+</keywords>
+</info>
+
+<reply>
+<data>
+HTTP/1.1 2 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+HTTP GET with single-digit reponse code
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/1431
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /1431 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+</protocol>
+</verify>
+</testcase>