misc/cgo/testcshared: don't leave garbages after test

Change-Id: I668b18b1e6901c59cf170e0c1cde9a3923c0cb13
Reviewed-on: https://go-review.googlesource.com/11472Reviewed-by: David Crawshaw <crawshaw@golang.org>

misc/cgo/testcshared/test.bash

@@ -28,7 +28,7 @@ fi
 androidpath=/data/local/tmp/testcshared-$$
 
 function cleanup() {
-	rm -rf libgo.so libgo2.so libgo.h testp testp2 testp3 pkg
+	rm -rf libgo.$libext libgo2.$libext libgo.h testp testp2 testp3 pkg
 
 	rm -rf $(go env GOROOT)/${installdir}