Add additional packages needed to generate the documentation on CentOS.
Change-Id: I355f3a95d4f484ab746e3d3985a031df5c0b24e5
libbabeltrace-dev libbabeltrace-ctf-dev
````
-4. For Centos 7.6 the following adds the needed packages:
+4. For CentOS 7.6 the following adds the needed packages:
````shell
yum install -y epel-release centos-release-scl
- yum install -y bison flex gcc make texinfo gcc-c++ \
+ yum install -y bison flex gcc make texinfo texinfo-tex gcc-c++ \
zlib-devel expat-devel python-devel xz-devel \
libbabeltrace-devel ncurses-devel
````