Rename Makefile.am.example => converter-example.mk

The generated Makefile.am.example is not really in the automake style.
Renaming it to converter-example.mk to reflect that it is a plain makefile
snippet and that it is for creating the converter-example
diff --git a/.gitignore b/.gitignore
index 34af5cf..7a03fc9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -43,6 +43,7 @@
 # /tests/
 /tests/tests-asn1c-smoke/Makefile.am.libasncodec
 /tests/tests-asn1c-smoke/Makefile.am.sample
+/tests/tests-asn1c-smoke/converter-example.mk
 /tests/tests-asn1c-smoke/*.[acho]
 /tests/tests-asn1c-smoke/*.asn
 /tests/tests-asn1c-smoke/*.txt
@@ -77,6 +78,7 @@
 /examples/sample.source.*/.tmp.*
 /examples/sample.source.*/Makefile.am.libasncodec
 /examples/sample.source.*/Makefile.am.example
+/examples/sample.source.*/converter-example.mk
 !/examples/sample.source.*/Makefile
 !/examples/sample.source.*/config.h