SubstanceGroup output doesn't correctly quote " symbols

[greglandrum]

Describe the bug
Here's the demonstration:

In [2]: m = Chem.MolFromMolBlock('''foo
   ...:      RDKit          2D
   ...: 
   ...:   0  0  0  0  0  0  0  0  0  0999 V3000
   ...: M  V30 BEGIN CTAB
   ...: M  V30 COUNTS 6 6 1 0 0
   ...: M  V30 BEGIN ATOM
   ...: M  V30 1 C -0.866400 -0.499400 0.000000 0
   ...: M  V30 2 C -0.865600 0.500600 0.000000 0
   ...: M  V30 3 C 0.000800 1.000000 0.000000 0
   ...: M  V30 4 C 0.866400 0.499400 0.000000 0
   ...: M  V30 5 C 0.865600 -0.500600 0.000000 0
   ...: M  V30 6 C -0.000800 -1.000000 0.000000 0
   ...: M  V30 END ATOM
   ...: M  V30 BEGIN BOND
   ...: M  V30 1 2 1 2
   ...: M  V30 2 1 2 3
   ...: M  V30 3 2 3 4
   ...: M  V30 4 1 4 5
   ...: M  V30 5 2 5 6
   ...: M  V30 6 1 1 6
   ...: M  V30 END BOND
   ...: M  V30 BEGIN SGROUP
   ...: M  V30 1 DAT 0 ATOMS=(1 1) FIELDNAME=[DUP]Tempstruct FIELDINFO="""" -
   ...: M  V30 FIELDDISP="    2.1037    1.5400    DA    ALL  0       0" QUERYOP="""" -
   ...: M  V30 FIELDDATA=Foo1
   ...: M  V30 END SGROUP
   ...: M  V30 END CTAB
   ...: M  END
   ...: ''')

In [3]: print(Chem.MolToV3KMolBlock(m))
foo
     RDKit          2D

  0  0  0  0  0  0  0  0  0  0999 V3000
M  V30 BEGIN CTAB
M  V30 COUNTS 6 6 1 0 0
M  V30 BEGIN ATOM
M  V30 1 C -0.866400 -0.499400 0.000000 0
M  V30 2 C -0.865600 0.500600 0.000000 0
M  V30 3 C 0.000800 1.000000 0.000000 0
M  V30 4 C 0.866400 0.499400 0.000000 0
M  V30 5 C 0.865600 -0.500600 0.000000 0
M  V30 6 C -0.000800 -1.000000 0.000000 0
M  V30 END ATOM
M  V30 BEGIN BOND
M  V30 1 2 1 2
M  V30 2 1 2 3
M  V30 3 2 3 4
M  V30 4 1 4 5
M  V30 5 2 5 6
M  V30 6 1 1 6
M  V30 END BOND
M  V30 BEGIN SGROUP
M  V30 1 DAT 0 ATOMS=(1 1) FIELDNAME=[DUP]Tempstruct FIELDINFO=" FIELDDISP="   -
M  V30  2.1037    1.5400    DA    ALL  0       0" QUERYOP=" FIELDDATA="Foo1"
M  V30 END SGROUP
M  V30 END CTAB
M  END

we can see that it's not a parsing problem:

In [4]: sgs = Chem.GetMolSubstanceGroups(m)

In [5]: sgs[0].GetPropsAsDict()
Out[5]: 
{'TYPE': 'DAT',
 'index': 1,
 'FIELDNAME': '[DUP]Tempstruct',
 'FIELDINFO': '"',
 'FIELDDISP': '    2.1037    1.5400    DA    ALL  0       0',
 'QUERYOP': '"',
 'DATAFIELDS': <rdkit.rdBase._vectNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE at 0x7f334d06c990>}

Expected behavior
" characters in SubstanceGroup output need to be enclosed in " and doubled.

Configuration (please complete the following information):

• RDKit version: master and releases
• OS: all