connman_test.sh: Rework for busybox 'ps'

connman_test.sh: Rework for busybox 'ps'

This script has two problems today.  First, it does 'ps -ef cmd'
in failure which real ps doesn't grok and busybox ps just ignores
the argument on.  Switch that to 'ps -ef'.  Second, busybox ps -o
doesn't understand cmd but does understand comm.  Using comm lets
us simplify the test logic as well, so switch to that.

(From OE-Core rev: cb34ce6833f298d487eeb35cf8297f286ef624d4)

Signed-off-by: Tom Rini <tom_rini@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>