force ./autogen.sh scripts to use automake-1.11

GnuPG does not work with automake 1.14, it has proven reliable on 1.11, and
that's widely available, so we'll add it to the env here, and the
./autogen.sh scripts will pick it up.

http://lists.gnupg.org/pipermail/gnupg-devel/2013-August/027857.html
replace SDK_BASE var with standard ANDROID_HOME

Unfortunately, the ANDROID_HOME var is not documented anywhere official,
but it is the most common variable on stackoverflow.com, and it is used in
the build.xml file that is generated by `android update project`.