Incorporate recent feedback from Remi, build once
    
    Drop modification of the configuration file to add
    systemd supervision - Remi correctly points out this
    is redundant (due to unit files already overriding)
    and will just cause issues.
    
    Noticed the build runs twice also, once during the
    %build phase and once again during %install (full
    rebuild) - this was because of differing options on
    the make lines (CFLAGS= etc vs PREFIX= etc) and the
    Redis src/Makefile causes full rebuild as a result
    (including of deps/* which it "make distclean"s).
    
    Also fixed a rpmbuild "warning: Macro expanded in
    comment" message in a couple of places, and changed
    the way we squash hidden build messages to use the
    "V" macro as the Makefiles intended.