Fix bug for Lambert Conformal grids straddling the international date line.

[JohnHalleyGotway]

This issue was raised via met-help:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=94492

MET is not handling GRIB1 or GRIB2 data correctly for the following grid:
1:0:vt=2016052012:500 mb:720 min fcst:TMP Temperature [K]:
ndata=18496:undef=0:mean=249.408:min=240.326:max=259.783
grid_template=30:winds(N/S):
Lambert Conformal: (136 x 136) input WE:SN output WE:SN res 48
Lat1 49.576424 Lon1 179.749024 LoV 190.000000
LatD 60.000000 Latin1 60.000000 Latin2 30.000000
LatSP 0.000000 LonSP 190.000000
North Pole (136 x 136) Dx 10000.000000 m Dy 10000.000000 m mode 48

[JohnHalleyGotway]

The problem and fix lie in the Lambert Conformal grid source code, lc_grid.cc.

The problem is that the longitudes of the lower-left corner and central longitude fall on opposite sides of the international date line. MET automatically rescales longitudes to put them into a standard range. One of the Lambert Conformal grid parameters is the difference between the lower-left and center longitudes. We had been getting a value of about 350 degrees, when we should have a value of about 10 degrees.

It's a one-line fix in src/libcode/vx_grid/lc_grid.cc.
OLD: theta_pin = HCone(Lon_orient - data.lon_pin);
NEW: theta_pin = HCone(rescale_deg(Lon_orient - data.lon_pin, -180.0, 180.0));

This rescales the resulting difference to the expected range of (-180, 180) and produces the desired result.

[JohnHalleyGotway]

met-help user confirmed that this change fixed the problem.