Replace sh with bash in Makefile
Replace sh with bash in Makefile

An invocation of sh -x caused the tests to fail on some systems that do
not link /bin/sh to /bin/dash. For increased portability all occurrences
of direct invocations of sh are replaced by invocations of bash.

FAU-Inf2/AuDoscore,FAU-Inf2/AuDoscore