Duplicate check_page_faults function

[adrianlzt]

Function check_page_faults is defined twice.

First one def check_page_faults(con, host, warning, critical, perf_data): And uses maintain_delta to compare results between executions.

This was added in f70dfa361b521ef344982451a4f008bf42feffdf and its action deleted here.

Second one def check_page_faults(con, sample_time, warning, critical, perf_data): Making two queries sleeping in between sample_time.

This was added aferwards in ff947e00533c669ac73adc9ee76b43a6cdf9935c