[pcp] RFC: pmie fqdn support

[Frank Ch. Eigler]

Hi -

I'd appreciate a review of the squashed solitary patch
git://sourceware.org/git/pcpfans.git branch fche/pmie.  It appears to
show no regressions in QA, and the new functionality (supporting
general "-h HOSTSPEC" strings) is OK by hand.  I'm assembling
mechanical QA for it now.  I'm thinking of extending it by adding
another action %-expansion code for the hostspec (%c), which would be
useful for letting other pcp clients reliably to the target server.


commit 1e33682da0f4211842065e480d8ce14000fa1089
Author: Frank Ch. Eigler <fche at redhat.com>
Date:   Fri Mar 7 21:35:36 2014 -0500   ** wow, started on this long ago **

    PR1105: fqdn -h support for pmie
    
    pmie's use of host names as interchangeable with pmNewContext
    connection strings was deeply embedded.  The new fields in structs
    'metric' and 'host' track a connection string alongside the host name.
    The newContext() function is now solely responsible for looking up
    host names from archive or real-time pmcd connections, and updating
    the pmie mmv data with it.  Some other functions that used to take an
    ambiguous name parameter now document which, or else take both.
    
    pmie diagnostic messages try to more consistently print one or the
    other, requiring many trivial qa/FOO.out updates.
    
    In the man page, pmie's -H (don't do dns lookup) became undocumented,
    since it has long been unimplemented.  A little bit of clarification
    regarding host names vs connection strings was added.
    
    Some const qualifiers to char*'s have been added,
    out of a sense of unchanging constervativeness.



- FChE