use same executable in forced and coupled mode for LMDZ

Use the same executable in forced and coupled mode for LMDZ Actually, there is an error during execution due to unusable MPI subroutines called in forced mode.

[0] Trace back of process [0,0]:
                 Called from mpisx_print_suspend_process ELN=?(4011b14a8) LANG=C
                 Called from mpisx_send_print_suspend ELN=?(4011b29f0) LANG=C
                 Called from mpisx_suspend ELN=?(4011b6308) LANG=C
                 Called from MPID_SHMEM_Check_incoming ELN=?(40113734c) LANG=C
                 Called from mpi_recv_ ELN=?(400fbd884) LANG=C
                 Called from prism_init_comp_proto ELN=695(400560378) LANG=F90
                 Called from mod_const_mpi.init_const_mpi ELN=16(40005d4a8) LANG=F90
                 Called from gcm ELN=480(4000014d8) LANG=F90
                 Called from main.o ELN=?(4012d4510) LANG=C

Error during execution of IPSLCM4_v2 after 3 days of simulation

This error occures after 3 days of IPSLCM4_v2 simulation at 192x142 resolution for LMDZ. The problem appears only if rugoro=0. is added in the routine physiq.F (line 1676).

  * 274 DPWR -> D1<0 in D1**D2 PROG=hbtm ELN=737(4004c5f1c)
****  99 Execution suspended PROG=hbtm ELN=737(4004c5f1c)
               Called from pbl_surface_mod.pbl_surface ELN=986(4003f00c8)
               Called from physiq ELN=5785(4001831d0)
               Called from calfis_p ELN=833(4000c30d0)
               Called from leapfrog_p ELN=1077(400055790)
               Called from gcm ELN=704(400001d80) 

Pmagic implementation

Add a parameter pmagic in albedo computation.

• Initialised in conf_phys.F90 or gcm.def
• Used in albedo.F