Problem of qsurf initialisation if non-empty traceur file but tracer=false

[jvatant]

If tracer=.false. in callphys.def but there is a tracer.def with tracers in it, then, as we don't go through initracer we just allocate 'noms' in physiq_mod but then phyetat0 and phyredem try to write or read qsurf based on noms which is not initialized (obviously crashing).

This is due to the fact that in such case dynamics sent a nq>0 whereas physics tracer=.false.

I suggest that we fix it either by either :

• Setting a tracer=true condition in the concerned part of phyetat0 phyredem and instead set qsurf to 0
• Reading properly the name which would enables to read its value and rewrite it at the end even without tracer (useful?), which will be consistent with dynamics
• Having a sanity check either aborting if tracer=false and nq>0, informing the user that a non-empty tracer.def must be used with tracer=true.

[jvatant]

Additional note : The pb also rise if no tracer.def in this case dynamics set nq=1 by default and same crash happens.