Fixes #3232. Properly initialized per-cell counters

[atrayano]

Types of change(s)

• [x ] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)
• Refactor (no functional changes, no api changes)

Checklist

• [x ] Tested this change with a run of GEOSgcm
• Ran the Unit Tests (make tests)

Description

Nullified propely the newly allocated per-cell counters

Related Issue

#3232