Remove conversions.sip conditionals meant for 4.12 but actually 4.18

- The hex version of 4.12 was not 0x041200 (current 4.18) but 0x040c00.
  Code was always skipped and has worked with recent sip versions.

python/core/conversions.sip

@@ -680,11 +680,6 @@ template<TYPE>
   PyObject *kobj, *tobj, *kobj2, *tobj2;
   Py_ssize_t i = 0;
 
-  //TODO: it works using SIP
-#if (SIP_VERSION >= 0x041200)
-  const sipMappedType* qmap2 = sipFindMappedType("QMap<int, TYPE>");
-#endif
-
   // Check the type if that is all that is required.
   if (sipIsErr == NULL)
   {
@@ -696,17 +691,12 @@ template<TYPE>
       if (!PyDict_Check(tobj))
         return 0;
 
-#if (SIP_VERSION >= 0x041200)
-      if (!sipCanConvertToMappedType(tobj, qmap2, SIP_NOT_NONE))
-        return 0;
-#else
       Py_ssize_t j = 0;
       while (PyDict_Next(tobj, &j, &kobj2, &tobj2))
       {
         if (!sipCanConvertToType(tobj2, sipType_TYPE, SIP_NOT_NONE))
           return 0;
       }
-#endif
     }
     return 1;
   }
@@ -717,24 +707,6 @@ template<TYPE>
   {
     qint64 k = PyLong_AsLongLong(kobj);
 
-#if (SIP_VERSION >= 0x041200)
-    // TODO: search for the minimum SIP version this code works on, it works
-    // on SIP 4.13.3 (GS). See #else to know why the version check is needed.
-
-    int state;
-
-    TYPE* t = reinterpret_cast<TYPE*>(sipConvertToMappedType(tobj, qmap2, sipTransferObj,SIP_NOT_NONE,&state,sipIsErr));
-
-    if (*sipIsErr)
-    {
-      sipReleaseMappedType(t, qmap2, state);
-      delete qm;
-      return 0;
-    }
-
-    qm.insert(k, *t);
-    sipReleaseMappedType(t, qmap2, state);
-#else
     // using sipConvertToMappedType to convert directly to QMap<int, TYPE> doesn't work
     // and ends with a segfault
 
@@ -759,7 +731,6 @@ template<TYPE>
       sipReleaseType(t2, sipType_TYPE, state);
     }
     qm->insert(k, qm2);
-#endif
   }
 
   *sipCppPtr = qm;