Fix to previous fix, to avoid overstepping bounds of zone_depths[] array.
Merge branch 'hotfix/VIC_4.1.2.h.2' of https://github.com/tbohn/VIC into hotfix/VIC_4.1.2.h

This is a late fix to the changes included in the 4.1.2.h tag.
Fixed the use of uninitialized soil moisture array on first time step.