configure: adjust openssl lib names on mingw

both the mingw and msvc build have a "lib" prefix on the libraries. this
makes the msvc build unconventional, so it needs an extra source. for
the mingw build, otoh, this is the expected setup, so the source used
for unix will work just fine.

this doesn't fix any actual bug, because mingw will apparently resolve
-llibfoo to libfoo.a even though only liblibfoo.a and libfoo.lib are
documented (on mingw.org). however, this mix of conventions is ugly and
should be avoided.

Change-Id: I32b1621e4ac15db1f071c08ced738bfdafdcc11b
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

src/network/configure.json

@@ -77,9 +77,12 @@
                 },
                 {
                     "libs": "-llibssl -llibcrypto",
-                    "condition": "config.win32"
+                    "condition": "config.msvc"
                 },
-                { "libs": "-lssl -lcrypto", "condition": "!config.win32" }
+                {
+                    "libs": "-lssl -lcrypto",
+                    "condition": "!config.msvc"
+                }
             ]
         }
     },