wininet: Fix a typo in is_basic_auth_value.

This fixes basic authentication when the server uses a realm string.
diff --git a/dlls/wininet/http.c b/dlls/wininet/http.c
index 0118d7b..d24bc43 100644
--- a/dlls/wininet/http.c
+++ b/dlls/wininet/http.c
@@ -394,7 +394,7 @@
 {
     static const WCHAR szBasic[] = {'B','a','s','i','c'}; /* Note: not nul-terminated */
     return !strncmpiW(pszAuthValue, szBasic, ARRAYSIZE(szBasic)) &&
-        ((pszAuthValue[ARRAYSIZE(szBasic)] != ' ') || !pszAuthValue[ARRAYSIZE(szBasic)]);
+        ((pszAuthValue[ARRAYSIZE(szBasic)] == ' ') || !pszAuthValue[ARRAYSIZE(szBasic)]);
 }
 
 static BOOL HTTP_DoAuthorization( LPWININETHTTPREQW lpwhr, LPCWSTR pszAuthValue,