Related to commit a3062b5f, let's also update the RPM spec file, its
configs/scripts and the README, to use /usr/bin instead of /usr/sbin.
While at it, noticed that el/ngcp-rtpengine-iptables-setup seemed to use
a wrong path (/sbin/rtpengine-get-table instead of
/usr/sbin/rtpengine-get-table), adjusted accordingly.
While at it, also fixed mixed-use-of-spaces-and-tabs issues (as reported
by rpmlint) in rtpengine.spec.
FTR, we have the following layout in the resulting RPMs now:
* /usr/bin/rtpengine
* /usr/bin/rtpengine-ctl
* /usr/bin/rtpengine-recording
* /usr/sbin/ngcp-rtpengine-iptables-setup
* /usr/sbin/rtpengine-get-table
Change-Id: I7e9e3527f4dc07adba425172cebb5672f2541690