Decide what to do about failing softlayer_spec test

[olleolleolle]

Bug report

#973 notes that one test fails.

Some digging was done into why that is.

Find a solution that includes an explanation - we don't want to end up with a test with "a jumbled history" that happens to pass.

The current version of the test has some superfluous code, even.

Current behavior:

Test fails. Could be duplicated elsewhere.

Steps to reproduce current behavior:

Run tests.

Expected behavior:

No duplicated test for this behaviour. No failures.

System information:

• ruby version: n/a
• savon version: current repo code