Revert "Add Debian to Install Guide title on docs.o.o"

This reverts commit f9f285ae9952d1cff2543ce27f3f781986b1a78d.

Some idiot (me) approved the previous commit against the advice at the
end of the commit message.

Change-Id: I70fbc4c9e31058f4a5b42c22120cd62b682c439f