Errant UZQSTO values being passed in flow-transport link (FTL) file

[emorway-usgs]

While running a mf-nwt simulation with a shallow water table in a number off cells adjacent to a lake and stream, UZQSTO values in cells where the water table was just above land surface (or just above the surfdep threshold) were frivolous. For example, the values in one region of the model next to a lake were as follows (note the values that are 7,000+ relative to the other values nearby):

arr2_o[2,187:195,165:170]
array([[    0.     ,     0.     ,     0.     ,     0.     ,     0.     ],
       [  -22.62087,   -17.76963,     0.     ,     0.     ,     0.     ],
       [  -26.48435,   -22.68177,     0.     ,     0.     ,     0.     ],
       [  -28.30317,   -26.84796,   -19.15605,     0.     ,     0.     ],
       [  -28.78178,   -28.50109,  7132.203  ,     0.     ,     0.     ],
       [  -28.72101,   -29.35501,   -27.47311,   -19.35728,     0.     ],
       [  -28.10455,   -29.2487 ,   -28.77859,  7132.781  ,     0.     ],
       [  -27.15882,   -28.81567,   -29.31157,   -27.30185,  7136.734  ]])

[emorway-usgs]

Tested the code change reflected in commit 1bea9a5 and seems to be writing legit UZQSTO values now (thanks Rich!). For example, the values shown above are now [note the absence of 7,000+ are now either 0 (cell is submerged, i.e., no unsat zone) or are in line with the other values (compare lower right value)]:

arr2_n[2,187:195,165:170]
array([[  0.     ,   0.     ,   0.     ,   0.     ,   0.     ],
       [-22.62087, -17.76963,   0.     ,   0.     ,   0.     ],
       [-26.48435, -22.68177,   0.     ,   0.     ,   0.     ],
       [-28.30317, -26.84796, -19.15605,   0.     ,   0.     ],
       [-28.78178, -28.50109, -23.44761,   0.     ,   0.     ],
       [-28.72101, -29.35501, -27.47311, -19.35728,   0.     ],
       [-28.10455, -29.2487 , -28.77859, -22.86927,   0.     ],
       [-27.15882, -28.81567, -29.31157, -27.30185, -18.91611]])