Fix a funny default service name, adjust test to be case-agnostic.
winmgmt on Windows XP and Windows 8 have different capitalization for this
service. I'm not sure why it's a module parameter though - the test will still
fail if its anything other than winmgmt.
The following RC script has 7 successful outputs when run against a reverse_tcp shell.
Run a reverse_tcp stager and the following RC script to run the test
```
loadpath test/modules
use exploit/multi/handler
set payload windows/meterpreter/reverse_tcp
set lhost 192.168.43.1
run -j
sleep 5
use post/test/services
set SESSION 1
run
```
Note: this test still doesn't run very reliably on windows 8 unless you're
using the code from rapid7/meterpreter#107 and #4411, though it runs ok on
Windows XP.
Brent Cook
0c94536b87