Font-dejavu is (now) an input of fontconfig. Specifying "dejavu sans" makes
generated images reproducible even when other fonts are installed (notably
font-google-noto).
* doc/images/bootstrap-graph.dot,
doc/images/bootstrap-packages.dot,
doc/images/coreutils-bag-graph.dot,
doc/images/coreutils-graph.dot,
doc/images/gcc-core-mesboot0-graph.dot,
doc/images/service-graph.dot,
doc/images/shepherd-graph.dot: Use fontname = "dejavu sans".
* doc/guix.texi (Full-Source Bootstrap): Update gcc-core-mesboot0.dot recipe
accordingly.
Change-Id: If21d7d39d45c66de5bceafb7b825a057d540ee50
076670f7ac
