AudioOutputOSS: Fix Coverity 700224. Unchecked return value (of fnctl)
Fix issues with earlier scheduler timing refactor.

Fix a few issues, that were intruduced in SHA1:a2eb9312, including the
failure to put inactive slaves to sleep.

Fixes #11578
Refs #11108
change type of counters to size_t to silence warnings about sign mismatch
change code to avoid multiple different types in initialization part of the loops
Eliminate (logically) dead code

After commit [ea554c9c] selTrack will never have the value -1
(it is assigned 0 in the block previous if it had that value).
Remove the (redundant) checks.

Fixes coverity 700308.
Fixes #11580
Remove redundant check

The codes check for numStream being zero previously,
and return from the function if it is zero.

Fixes #11581
Fix for (likely) typo in checking setsockopt return code

There was a logic error due to an errant parenthesis
that was (likely) intended to be used to check the
return code from setsockopt, but instead resulted in
a value of zero being used for the length of the
operand.  This patch moves the right paren to where
it should have been.

Fixes coverity 746821
Fixes #11582
Merge remote-tracking branch 'upstream/master'