Adding the port parameter to the borg handler with a default value of 22
is causing issues for users who had been using the standard ssh config
file to set the remote port, since the -p cli argument overrides the
configuration. This removes the default port number and only uses it in
the connection string if defined.
This is part of a fix for reproducible builds where usrmerge may or may
not be in effect on the build system. We need to be able to pass the
BASH envvar to autotools so its able to correctly determine the correct
path for bash. The lines removed here were added to fix DEBBUG-346303
but should not be required on a clean build environment, where BASH
remains unset unless the current shell is actually BASH, and when it is,
should return the correct path to the bash executable and not /bin/sh.
