EAMxx: avoid nullptr when reading horiz remap sparse matrix entries

A std vector of length 0 is not allocated, resulting in invalid memory

components/eamxx/src/share/grid/remap/horiz_interp_remapper_data.cpp

@@ -49,9 +49,11 @@ get_my_triplets (const std::string& map_file) const
   int nlweights = scorpio::get_dimlen_local(map_file,"n_s");
 
   // 1.1 Read a chunk of triplets col indices
-  std::vector<gid_type> cols(nlweights);
-  std::vector<gid_type> rows(nlweights);
-  std::vector<Real>  S(nlweights);
+  // NOTE: add 1 so that we don't pass nullptr to scorpio read routines (which would trigger
+  //       a runtime error). Don't worry though: we never access the last entry of these vectors
+  std::vector<gid_type> cols(nlweights+1,-1);
+  std::vector<gid_type> rows(nlweights+1,-1);
+  std::vector<Real>  S(nlweights+1,0);
 
   // Figure out if we are reading the right map, that is:
   //  - n_a or n_b matches the fine grid ncols