debian: Make git ignore several intermediate files.

The "make release" target doesn't cause these to be left around, but
manually doing something like ./debian/rules/build can.

diff --git a/debian/.gitignore b/debian/.gitignore
new file mode 100644 (file)
index 0000000..801ca02
--- /dev/null
+++ b/debian/.gitignore
@@ -0,0 +1,3 @@
+*.debhelper
+*.debhelper.log
+*.substvars