network: correlation with missing values

[Former user]

in the network function line 369, I propose to change coordj = cor(mat$Xk[, keep], mat$variatesk[, compk]) into coordj = cor(mat$Xk[, keep], mat$variatesk[, compk], use ="pairwise") as for other cor in the function

[Florian Rohart]

commit 8b85e79