test_bash: don't use dc anymore during tests
test_bash: don't use dc anymore during tests

Use only "cat", "echo" and "sort" which are more likely to be there. Using less
standard programs breaks TravisCI.

Signed-off-by: Rodrigo Tobar <bd955c861cbec2e41c0959cf13c7f573fa307e58@icrar.org>

steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge