When an error occurs solving the linear system, the matrix is written on stderr and an exception is thrown even if the deconvolution continues

[ERROR] [FATAL] failed to set lp output to:
	null
java.lang.NullPointerException
	at java.io.FileOutputStream.<init>(FileOutputStream.java:201)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
	at barna.flux.capacitor.reconstruction.GraphLPsolver.run(GraphLPsolver.java:946)
	at barna.flux.capacitor.reconstruction.FluxCapacitor$LocusSolver.run(FluxCapacitor.java:249)
	at barna.flux.capacitor.reconstruction.FluxCapacitor.solve(FluxCapacitor.java:2131)
	at barna.flux.capacitor.reconstruction.FluxCapacitor.explore(FluxCapacitor.java:2665)
	at barna.flux.capacitor.reconstruction.FluxCapacitor.call(FluxCapacitor.java:1728)
	at barna.flux.capacitor.reconstruction.FluxCapacitor.call(FluxCapacitor.java:76)
	at barna.commons.launcher.Flux.main(Flux.java:212)