Bug 1338651 was backed out because when building a newer image, there
was a valgrind leak report that couldn't resolve symbols. Further
investigation showed the valgrind package installed had symbols stripped.
We upgrade valgrind version and build it from source with symbols.
We had to build inside the docker image because we need to run
"make install". Using "make dist" to generate a tar ball will also run
"make docs", and it is hard to make it work because of the outdated
texlive package present in CentOS 6.
We also apply a patch [1] to valgrind correctly generate symbols
for unloaded objects.
[1] https://bugs.kde.org/show_bug.cgi?id=79362#c62
MozReview-Commit-ID: 2IhuJY28Ke3
Wander Lairson Costa