Small fix in Makefile for JPetSigChTest.
Small fix in Makefile for JPetSigChTest.

JPETTomography/j-pet-framework,wkrzemien/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,JPETTomography/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework,JPETTomography/j-pet-framework