configure: bump automake requirement to 1.14 and autoconf to 2.69
configure: bump automake requirement to 1.14 and autoconf to 2.69

This is only required for builds from git, people can still
build tarballs if they only have older autotools.

https://bugzilla.gnome.org//show_bug.cgi?id=747624

rawoul/gst-plugins-good,hizukiayaka/gst-plugins-good,GrokImageCompression/gst-plugins-good,chamois94/gst-plugins-good,shelsonjava/gst-plugins-good,StreamUtils/gst-plugins-good,rawoul/gst-plugins-good,sebras/gst-plugins-good,sebras/gst-plugins-good,sebras/gst-plugins-good,Kurento/gst-plugins-good,hizukiayaka/gst-plugins-good,froggatt/gst-plugins-good-m,chamois94/gst-plugins-good,hizukiayaka/gst-plugins-good,rawoul/gst-plugins-good,kittee/gst-plugins-good,rawoul/gst-plugins-good,ikonst/gst-plugins-good,Kurento/gst-plugins-good,stfl/gst-plugins-good,froggatt/gst-plugins-good-m,chamois94/gst-plugins-good,ikonst/gst-plugins-good,GrokImageCompression/gst-plugins-good,Kurento/gst-plugins-good,chamois94/gst-plugins-good,StreamUtils/gst-plugins-good,GStreamer/gst-plugins-good,shelsonjava/gst-plugins-good,hizukiayaka/gst-plugins-good,pexip/gst-plugins-good,stfl/gst-plugins-good,ikonst/gst-plugins-good,Kurento/gst-plugins-good,vatavuserban/gst-plugins-good,pexip/gst-plugins-good,GrokImageCompression/gst-plugins-good,GStreamer/gst-plugins-good,GrokImageCompression/gst-plugins-good,stfl/gst-plugins-good,vatavuserban/gst-plugins-good,ikonst/gst-plugins-good,pexip/gst-plugins-good,froggatt/gst-plugins-good-m,pexip/gst-plugins-good,shelsonjava/gst-plugins-good,stfl/gst-plugins-good,vatavuserban/gst-plugins-good,Kurento/gst-plugins-good,pexip/gst-plugins-good,vatavuserban/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,StreamUtils/gst-plugins-good,kittee/gst-plugins-good,kittee/gst-plugins-good,shelsonjava/gst-plugins-good,sebras/gst-plugins-good,kittee/gst-plugins-good,froggatt/gst-plugins-good-m,GStreamer/gst-plugins-good