Fix pandoc error (producing PDF from TeX source)

Complete message:
Exception: error running command:
pandoc --standalone --toc --number-sections
--include-in-header=pdf-header-includes.txt --variable=geometry:a4paper
--variable=fontsize:12pt --variable=documentclass:book
--variable=graphics:1 --listings -o
/Users/st/projects/SlipStreamDocumentation/docs/administrator-manual/tar
get/results/administrator-manual.pdf title.txt 00-legal.md
01-introduction.md 02-prerequisites.md 03-building.md
04-installation.md 05-configuration.md 06-maintenance.md
07-cloud-connectors.md
output:
! Undefined control sequence.

\@titlepic ->\oldincludegraphics

                                 [width=0.7\textwidth
]{images/sixsq.png}

l.116 \maketitle