debian: add less as a build dependency
For builds that run on hermetic environments, it's possible that the "less"
package is not installed by default, yet it's needed for tests to pass after
revision
bf5e13e38390 (which sets less as the fallback pager).
--- a/contrib/debian/control Thu May 25 23:42:37 2017 -0400
+++ b/contrib/debian/control Fri May 26 19:33:20 2017 -0700
@@ -5,6 +5,7 @@
Build-Depends:
debhelper (>= 9),
dh-python,
+ less,
netbase,
python-all,
python-all-dev,