Changeset 4384 for trunk

Clairifications on t2m variable names. No changes in the calculation.

• sechiba : remove t2mdiag and use directly temp_air. t2mdiag was only a copy of temp_air done in enerbil.
• enerbil_t2mdiag : remove. This subroutine was only used to create a variable t2mdiag=temp_air.
• eneribil_initialize : remove variable temp_air et t2mdiag
• slowproc_main : rename t2m into temp_air to correspond to the current content of the variable. Remove t2m_min.
• stomate_main : remove t2m_min. This variable is calculated in stomate_main using t2m.

Note that stomate_initialize recieves the true t2m but stomate_main recieves temp_air. Same as before this commit.

See also ticket #372