Untested behavior if max nb of iterations reached in colgen

[guimarqu]

Solving the play gap instance with the simple branch and price strategy with nb_max_it = 10 in colgen algorithm yields an error.

[guimarqu]

In master :

replace colgen.jl:338 by if nb_cg_iterations > 10 ##TDalg_data.max_nb_cg_iterations

Max number of iterations reached in root node.
Error in node 4 :

<it=1> <et=12> <mst=0.000> <sp=0.000> <cols=1> <mlp=5073.7500> <DB=100.5000> <PB=76.0000>
play gap: Error During Test at /Users/gmarqu100p/.julia11/dev/Coluna/test/full_instances_tests.jl:7
  Got exception outside of a @test
  KeyError: key MathOptInterface.VariableIndex(-1) not found
  Stacktrace:
   [1] getindex at ./dict.jl:478 [inlined]
   [2] get_column at /Users/gmarqu100p/.julia11/packages/LinQuadOptInterface/HHper/src/variables.jl:10 [inlined]
   [3] modify(::GLPK.Optimizer, ::MathOptInterface.ObjectiveFunction{MathOptInterface.ScalarAffineFunction{Float64}}, ::MathOptInterface.ScalarCoefficientChange{Float64}) at /Users/gmarqu100p/.julia11/packages/LinQuadOptInterface/HHper/src/objective.jl:188
   [4] update_cost_in_optimizer!(::Coluna.MoiOptimizer, ::Coluna.Variable) at /Users/gmarqu100p/.julia11/dev/Coluna/src/MOIinterface.jl:56
   [5] sync_solver!(::Coluna.MoiOptimizer, ::Coluna.Formulation{Coluna.DwMaster}) at /Users/gmarqu100p/.julia11/dev/Coluna/src/optimizerwrappers.jl:96

[guimarqu]

There is also a "subissue" :

<it=10> <et=9> <mst=0.000> <sp=0.000> <cols=2> <mlp=72.6667> <DB=67.5000> <PB=89.0000>
<it=11> <et=9> <mst=0.000> <sp=0.000> <cols=1> <mlp=72.6667> <DB=69.0000> <PB=89.0000>
┌ Warning: Maximum number of column generation iteration is reached.

We should stop at iteration 10.