deb: fix OBS build

Add explicit dependency on python3 which is necessary for 'make check'
stage. While at it, add DH_VERBOSE option for debian/control to
facilitate future troubleshooting.

Change-Id: I0ed0bb0f889d4569c9229f3f12ad8bdb11cc1e7c
Related: OS#1948
diff --git a/debian/rules b/debian/rules
index 8797d5a..d0ad702 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,5 +1,6 @@
 #!/usr/bin/make -f
 
+#export DH_VERBOSE=1
 export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 
 %: