PCP Updates: pmcollectl record mode fails with sub-second intervals

[Stan Cox <scox@xxxxxxxxxx>]

Improve pmcollectl and pmatop log writing.

 * pmatop.py (record): Parse the log duration arg.
   Sleep with pmtimevalSleep.
   (main): Get the host name.  Parse the interval arg and use the result.
 * pmcollectl.py (record): Parse the log duration arg.
    Sleep with pmtimevalSleep.
    main): Allow -iN.  Parse the interval arg and use the result.
 * 709: Check it.
 * 722: Check it.

ssh://sourceware.org/git/pcpfans.git scox/dev commit 551df147760