Raise package version for native packaging in Git

Otherwise it looks like a package with orig sources sitting in
a foreign tree to git-buildpackage:

| + git-buildpackage -nc --git-force-create --git-ignore-new -S -us -uc --git-verbose --git-builder=/bin/true --git-cleaner=/bin/true
| /bin/true [] []
| fatal: Not a valid object name upstream/1.4.24.1
| ngcp-asterisk_1.4.24.1.orig.tar.gz does not exist, creating from 'upstream'

Moving to this version number schema instead fixes the
build issue.

Closes: https://jenkins.mgm.sipwise.com/job/asterisk-source/81/

debian/changelog

@@ -1,3 +1,10 @@
+ngcp-asterisk (1.4.24.1+ngcp.1) unstable; urgency=low
+
+  * Non-maintainer upload, adjusting package version for native
+    packaging in Git.
+
+ -- Michael Prokop <mprokop@sipwise.com>  Tue, 07 May 2013 17:34:02 +0200
+
 ngcp-asterisk (1.4.24.1-rsp+svn4100.5) unstable; urgency=low
 
   [ agranig ]