Avoid detaching in QBasicTimer

Amends da12a40b8b

Change-Id: I2a9e46844a88f7ee239c7306abca3d2c8f7b53d9
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/corelib/kernel/qtimerinfo_unix.cpp

@@ -390,7 +390,7 @@ qint64 QTimerInfoList::timerRemainingTime(int timerId)
     repairTimersIfNeeded();
     timespec tm = {0, 0};
 
-    for (const auto *t : *this) {
+    for (const auto *t : qAsConst(*this)) {
         if (t->id == timerId) {
             if (currentTime < t->timeout) {
                 // time to wait