Removing latent_evap from list of obsolete diagnostics

- In PR mom-ocean#163, @nicjhan has a commmit where is resolved a conflict
  between a registration of 'latent_evap' with the same being
  in the list of obsolete diagnostics.
- We reverted that commit and removed 'latent_evap' from the obsolete
  list. We are not entirely sure this was the right thing to do.
  - Signed Nic and Alistair.
- No answer changes.

src/diagnostics/MOM_obsolete_diagnostics.F90

@@ -46,7 +46,6 @@ subroutine register_obsolete_diagnostics(param_file, diag)
   if (found_in_diagtable(diag, 'precip_heat_content', 'heat_content_lprec')) foundEntry = .true.
   if (found_in_diagtable(diag, 'evap_heat_content', 'heat_content_massout')) foundEntry = .true.
   if (found_in_diagtable(diag, 'runoff_heat_content', 'heat_content_lrunoff')) foundEntry = .true.
-  if (found_in_diagtable(diag, 'latent_evap')) foundEntry = .true.
   if (found_in_diagtable(diag, 'latent_fprec')) foundEntry = .true.
   if (found_in_diagtable(diag, 'latent_calve')) foundEntry = .true.
   if (found_in_diagtable(diag, 'heat_rest', 'heat_restore')) foundEntry = .true.