Ref #291 - setOption(Memcached::OPT_PREFIX_KEY => false) should return false

[SjonHortensius]

No description provided.

[sodabrew]

The tests seem to disagree with the expectation:

========DIFF========
013+ bool(true)
013- 
014- Warning: Memcached::setOptions(): error setting memcached option: %s in %s on line %d
015- bool(false)
========DONE========
FAIL Set options using setOptions [tests/setoptions.phpt] 

[SjonHortensius]

I added this test to demonstrate that setOption(prefix, somethingincorrect) is broken since it should return false; but actually returns true.

To make this test succeed; the setOption needs to be fixed

[SjonHortensius]

I actually think this is fixed by #294; which casts somethingincorrect to an empty string implicitly