proxy: fix tests as follow-up to 93b0d907d5

This fixes tests that were added after 113f04e664 as the tests would
fail otherwise.

We bring back "Proxy-Connection: Keep-Alive" now unconditionally to fix
regressions with old and stupid proxies, but we could possibly switch to
using it only for CONNECT or only for NTLM in a future if we want to
gradually reduce it.

Fixes #954

Reported-by: János Fekete

tests/data/test1141

@@ -58,10 +58,12 @@ HTTP redirect to http:/// (three slashes!)
 GET http://%HOSTIP:%HTTPPORT/want/1141 HTTP/1.1
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
+Proxy-Connection: Keep-Alive
 
 GET http://foo.example.com/want/11410001 HTTP/1.1
 Host: foo.example.com
 Accept: */*
+Proxy-Connection: Keep-Alive
 
 </protocol>
 </verify>

tests/data/test1142

@@ -53,6 +53,7 @@ HTTP redirect to http://// (four slashes!)
 GET http://%HOSTIP:%HTTPPORT/want/1142 HTTP/1.1
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
+Proxy-Connection: Keep-Alive
 
 </protocol>
 # 3, CURLE_URL_MALFORMAT for the four slashes

tests/data/test1244

@@ -54,6 +54,7 @@ http://%HOSTIP:%HTTPPORT/1244 -x %HOSTIP:%HTTPPORT --next http://%HOSTIP:%HTTPPO
 GET http://%HOSTIP:%HTTPPORT/1244 HTTP/1.1
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
+Proxy-Connection: Keep-Alive
 
 </protocol>
 </verify>

tests/data/test2050

@@ -64,6 +64,7 @@ http://www.example.com.2050/2050 --connect-to ::connect.example.com.2050:%HTTPPO
 <proxy>
 CONNECT connect.example.com.2050:%HTTPPORT HTTP/1.1
 Host: connect.example.com.2050:%HTTPPORT
+Proxy-Connection: Keep-Alive
 
 </proxy>
 <protocol>