CRASH on close score after deleting all segment of a spanner

OP: https://musescore.org/en/node/105941

Reproduction steps:

1. open slures.mscz
2. right click slur
3. select all similar elements
4. delete
5. close score (don't need to bother saving)

Result: SIGSEGV with call stack:

1	??				
2	Ms::Element::name	element.cpp	245	0x11c24d5	
3	Ms::RemoveElement::cleanup	undo.cpp	1655	0x1363ca6	
4	Ms::UndoCommand::cleanup	undo.cpp	131	0x135c3f6	
5	Ms::UndoStack::~UndoStack	undo.cpp	198	0x135c63e	
6	Ms::Score::~Score	score.cpp	433	0x127d7d1	
7	Ms::Score::~Score	score.cpp	437	0x127da74	
8	Ms::MuseScore::removeTab	musescore.cpp	2066	0xbf1534	
9	Ms::MuseScore::qt_static_metacall	moc_musescore.cpp	798	0x1031238	
10	QMetaObject::activate	qobject.cpp	3730	0x7fffef483870	
11	Ms::ScoreTab::tabCloseRequested	moc_scoretab.cpp	172	0x10384ae	
12	Ms::ScoreTab::qt_static_metacall	moc_scoretab.cpp	94	0x10381c1	
13	QMetaObject::activate	qobject.cpp	3730	0x7fffef483870	
14	QMetaObject::activate	qobject.cpp	3595	0x7fffef484147	
15	QTabBar::tabCloseRequested	moc_qtabbar.cpp	339	0x7ffff031c781	
16	QMetaObject::activate	qobject.cpp	3730	0x7fffef483870	
17	QMetaObject::activate	qobject.cpp	3595	0x7fffef484147	
18	QAbstractButton::clicked	moc_qabstractbutton.cpp	307	0x7ffff05072f2	
19	QAbstractButtonPrivate::emitClicked	qabstractbutton.cpp	533	0x7ffff0275484	
20	QAbstractButtonPrivate::click	qabstractbutton.cpp	526	0x7ffff0276937	
...	

Stopped at this line:

const char* Element::name() const
      {
      return name(type());

Happens on Win 8.1 x86-64 2.0.3 and Arch Linux x86-64 latest master. And Jojo says on Win 7. And original reporter say win10 32bit.