Fixes non-BFB issue with F-compsets when threading is used

This PR addresses an issue which makes the model non-deterministic
(i.e. non-BFB) when run with more than one thread. PR #1147 introduced
a logical variable (cldfsnow_logic) which was declared and assigned at
module level. This kind of declaration automatically sets a variable
with 'SAVE' attribute which in turn makes the variable a shared variable
(to be shared by all the threads). This PR removes this variables and
retain the same functionality.

Fixes #1203

[BFB] - Bit-For-Bit

share/csm_share/README

@@ -0,0 +1,31 @@
+!===============================================================================
+! SVN $Id: README 19883 2009-12-14 23:19:10Z erik $
+! SVN $URL: https://svn-ccsm-models.cgd.ucar.edu/csm_share/trunk_tags/share3_150116/README $
+!===============================================================================
+
+                  A description of csm_share
+
+This module exists to collect code shared between various CCSM components.
+Excluding this "shared code" module, CCSM components are built using disjoint
+sets of source code.  The use of this shared code is similar to the use of
+object code libraries where each subdirectory of csm_share is equivalant to 
+one library.  While object library routines are accessed by linking to libraries 
+during the load phase, these shared code routines are accessed by including the 
+appropriate source code directory path during the compile phase.
+
+Motivation for this code sharing includes:
+
+- facilitating consistent physics between all models.  For example, uniform 
+  solar-zenith-angle/orbital calculations and uniform physical constants.
+- providing an interface/API between component models and the flux-coupler
+  component in the CCSM framework.
+- avoiding the need for redundant implementations of commonly needed 
+  functionality.  For example netCDF file reading, basic mapping (re-gridding)
+  functionality, and common character string manipulations.
+
+Current subsets ("libraries") of shared code only include:
+
+shr - very generic, general-purpose code that is likely to be useful to all 
+      CCSM components.  CCSM components may be explicitly required to use some 
+      parts of this code, for example the physical constants module.
+