Changes default value of cdrag_grounding

- A non-zero default value turns on grounding which changes exisiting
  configurations making it hard to upgrade the code in those configs.
  This sets the default to 0. The grounding tests already has a non-zero
  value in the input.nml and so still tests the grounding code.

src/icebergs_framework.F90

@@ -387,7 +387,7 @@ module ice_bergs_framework
   real :: spring_coef !< Spring constant for bonded iceberg interactions
   real :: contact_spring_coef !<Spring coefficient for berg collisions -Alex
   character(len=11) :: fracture_criterion !<'strain_rate','strain',or 'none'
-  real :: cdrag_grounding
+  real :: cdrag_grounding=0.0 !< Drag coefficient against ocean bottom
   real :: h_to_init_grounding
   real :: frac_thres_n !normal fracture strain threshold
   real :: frac_thres_t !tangential fracture strain threshold
@@ -587,7 +587,7 @@ subroutine ice_bergs_framework_init(bergs, &
 real :: spring_coef=1.e-8 ! Spring constant for iceberg interactions (this seems to be the highest stable value)
 real :: contact_spring_coef=0. !Spring coef for berg collisions (is set to spring_coef if not specified)
 character(len=11) :: fracture_criterion='none' !<'strain_rate','strain',or 'none'
-real :: cdrag_grounding=20.0
+real :: cdrag_grounding=0.0 ! Drag coefficient against ocean bottom
 real :: h_to_init_grounding=100.0
 real :: frac_thres_n=0.0 !normal fracture strain threshold
 real :: frac_thres_t=0.0 !tangential fracture strain threshold