Previous fix used %q which incorrectly go-escaped things. For example:
```
RUN echoo A \& B C
```
would result in the user seeing:
```
INFO[0000] The command '/bin/sh -c echoo A \\& B\tC' returned a non-zero code: 127
```
Note the double-\ and the \t instead of a tab character
The testcase had to double escape things due to logrus getting in the way
but I'm going to fix that in another PR because its a change to the UX.
Signed-off-by: Doug Davis <dug@us.ibm.com>
006c066b6c