buildserver: use automake and cmake from jessie-backports

buildserver: use automake and cmake from jessie-backports

These should be reasonably backwards compatible, and there is already
automake1.11 for those that need a version that old.  As for cmake, there
are five apps that seem to it:

com.amaze.filemanager
org.dolphinemu.dolphinemu
org.navitproject.navit
org.yabause.android
org.videolan.vlc

It looks like VLC is the only app that is currently building and using
cmake in the most recent releases.  Some of them used to use cmake, but no
longer.