autotest: switched examples build to navio

apm2 no longer supported. Navio provides good coverage of the code for
example builds

Tools/scripts/build_examples.sh

@@ -6,7 +6,7 @@
 set -e
 set -x
 
-targets="clean apm2"
+targets="clean navio"
 
 [ $# -gt 0 ] && {
     targets="$*"