Let test.sh decide if bash, not Makefile

[cdrage]

We should let test.sh decide whether to use bash or not, rather than Makefile.

Errors if not in sh / bash.

dropbox/dev/atomic  master ✔                                                                                                                                                                                                                              1d  
▶ sudo make test
sh ./test.sh
./test.sh: 2: set: Illegal option -o pipefail
Makefile:14: recipe for target 'test' failed
make: *** [test] Error 2

after PR:

dropbox/dev/atomic  fix-makefile ✔                                                                                                                                                                                                                        1m  
▶ sudo make test
./test.sh
Pulling standard images from Docker Hub...

[cdrage]

Jenkins failed? :(

Some tests run in sh rather than bash?

[rhatdan]

LGTM