SDP-1396: Emergency Bug Fix.
opt_perforce_sdp_backup.sh hardcodes the
premature /opt/perforce/p4-sdp OS package path instead of
/opt/perforce/helix-sdp, independently of the SDPPackageBase variable
already fixed by SDP-1394. Same fix as already applied to dev (change
33658): corrected the backup/staging directory names, the tar command's
internal structure, the -man usage text, plus 4 related stale comment
references in mkdirs.sh/install_sdp.sh.