Don't use bash in shell scripts unless bash is really needed.

When building ModemManager 1.18.4 in OpenEmbedded for a target using Busybox, the build fails on a quality control error because some of the scripts in the package have #!/bin/bash as the first line. It would be fine to specify bash if the scripts are, in fact, using bash-specific features, but they look like plain old Bourne shell scripts to me. I'm attaching the patch file that I used to work around the issue in OpenEmbedded. Since I'm not using any of the scripts in my project, I have not run them.

0001-Switched-bash-shell-scripts-to-use-bin-sh-for-use-w-.patch