hostip: bad CURLOPT_RESOLVE syntax now returns error

Added test 3019
Fixes #7170
Closes #7174

lib/hostip.c

@@ -1104,10 +1104,10 @@ CURLcode Curl_loadhostpairs(struct Curl_easy *data)
       error = false;
    err:
       if(error) {
-        infof(data, "Couldn't parse CURLOPT_RESOLVE entry '%s'!\n",
+        failf(data, "Couldn't parse CURLOPT_RESOLVE entry '%s'!",
               hostp->data);
         Curl_freeaddrinfo(head);
-        continue;
+        return CURLE_SETOPT_OPTION_SYNTAX;
       }
 
       /* Create an entry id, based upon the hostname and port */

tests/data/Makefile.inc

@@ -234,4 +234,6 @@ test3000 test3001 test3002 test3003 test3004 test3005 test3006 test3007 \
 test3008 test3009 test3010 test3011 test3012 test3013 test3014 test3015 \
 test3016 \
 \
-test3017 test3018
+test3017 test3018 \
+\
+test3019

tests/data/test3019

@@ -0,0 +1,36 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+--resolve
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<name>
+HTTP with invalid --resolve syntax
+</name>
+<command>
+--resolve %HTTPPORT:example.com:%HOSTIP http://example.com:%HTTPPORT/%TESTNUMBER
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<errorcode>
+49
+</errorcode>
+</verify>
+</testcase>