TST: test_fast.sh and test_multi.sh should skip network tests
@jreback @jtratner @y-p any objections? totally minor, but if someone is using these, `@network` tests will be run.
 ok
 back to the way it used to be. good.
 @y-p FWIW, it was only ever that way because `@network` tests were also marked as `@slow` which results in such tests not being run on Travis.
