This commit addresses issues that were seen when using ncdata with
longitudes in the [-pi, pi] range in cases with full physics.  This
would cause the atmosphere to become unphysical and runs to fail. This
change is made just after the longitude values are read to ensure they
are correct for the remainder of execution.

NOTE: this is before the 'aux_cam' tests have been run

Previous versions of the lonCell_arr adjustment used an explicit loop. Without this loop, the nCells variable and the routine to fetch it are no longer needed.

Makes code consistent with CAM coding standards: 'All variables of type
real must have a specified kind, including literals.'

This commit also extends the comment that was with this code block,
includes an if condition so valid values aren't modified, uses kinds and
constants (pi) that are already used in the new file, and updates the
ChangeLog so the correct file is referenced.

Conform to CAM Coding Standards: 'Use symbolic numerical comparison
operators (e.g., ==, /=, <, >=) not old character versions (e.g.,
.eq.).'