UBUNTU: [Packaging] startnewrelease: add support for backport kernels

BugLink: http://bugs.launchpad.net/bugs/1793461

Update the startnewrelease target to support backport version numbers
when creating the new changelog entry.
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

debian/rules.d/1-maintainer.mk

@@ -120,11 +120,10 @@ diffupstream:
 
 startnewrelease:
 	dh_testdir
-	@nextminor=$(shell expr `echo $(revision) | gawk -F. '{print $$2}'` + 1); \
-	nextmajor=$(shell expr `echo $(revision) | awk -F. '{print $$1}'` + 1); \
+	@ver=$$(echo "$(revision)" | perl -ne 'if (/^(\d*)\.(\d*)(.*)?$$/) { printf("%d.%d%s\n", $$1 + 1, $$2 +1, $$3) }'); \
 	now="$(shell date -R)"; \
-	echo "Creating new changelog set for $(release)-$$nextmajor.$$nextminor..."; \
-	echo -e "$(src_pkg_name) ($(release)-$$nextmajor.$$nextminor) UNRELEASED; urgency=medium\n" > $(DEBIAN)/changelog.new; \
+	echo "Creating new changelog set for $(release)-$$ver..."; \
+	echo -e "$(src_pkg_name) ($(release)-$$ver) UNRELEASED; urgency=medium\n" > $(DEBIAN)/changelog.new; \
 	echo "  CHANGELOG: Do not edit directly. Autogenerated at release." >> \
 		$(DEBIAN)/changelog.new; \
 	echo "  CHANGELOG: Use the printchanges target to see the curent changes." \