cookies: only consider full path matches

I found a bug which cURL sends cookies to the path not to aim at.
For example:
- cURL sends a request to http://example.fake/hoge/
- server returns cookie which with path=/hoge;
  the point is there is NOT the '/' end of path string.
- cURL sends a request to http://example.fake/hogege/ with the cookie.

The reason for this old "feature" is because that behavior is what is
described in the original netscape cookie spec:
http://curl.haxx.se/rfc/cookie_spec.html

The current cookie spec (RFC6265) clarifies the situation:
http://tools.ietf.org/html/rfc6265#section-5.2.4

tests/data/test1228

@@ -0,0 +1,54 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+cookies 
+cookie path
+</keywords>
+</info>
+<reply>
+<data>
+HTTP/1.1 200 OK
+Date: Tue, 25 Sep 2001 19:37:44 GMT
+Set-Cookie: path1=root; domain=.example.fake; path=/;
+Set-Cookie: path2=depth1; domain=.example.fake; path=/hoge;
+Content-Length: 34
+
+This server says cookie path test
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+HTTP cookie path match
+ </name>
+ <command>
+http://example.fake/hoge/1228 http://example.fake/hogege/ -b nonexisting -x %HOSTIP:%HTTPPORT
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET http://example.fake/hoge/1228 HTTP/1.1
+Host: example.fake
+Accept: */*
+Proxy-Connection: Keep-Alive
+
+GET http://example.fake/hogege/ HTTP/1.1
+Host: example.fake
+Accept: */*
+Proxy-Connection: Keep-Alive
+Cookie: path1=root
+
+</protocol>
+</verify>
+</testcase>