Use Qt 5's QStringList::join(QChar)

Less typing and less cycles than join(QString) where appropriate

Change-Id: I6ebc0e17e4d7fd9845864dd95b7de4ba4dad6906
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/projectexplorer/abi.cpp

@@ -527,7 +527,7 @@ QString Abi::toString() const
     dn << toString(m_binaryFormat);
     dn << toString(m_wordWidth);
 
-    return dn.join(QLatin1String("-"));
+    return dn.join(QLatin1Char('-'));
 }
 
 bool Abi::operator != (const Abi &other) const