MT#21523 fix package version to fit debian native rules

We have 1.4.24.1+ngcp.1 in 3.0, previous version in 2.8 is 1.4.24.1-rsp+svn4100.5

> dpkg --compare-versions 1.4.24.1-rsp+svn4100.5 lt 1.4.24.1rsp+svn4100.6; echo $?
> 0
> dpkg --compare-versions 1.4.24.1rsp+svn4100.6 lt 1.4.24.1+ngcp.1 ; echo $?
> 0

Change-Id: I7bc6838a3713885c137c592a344b3778e2eb619a

debian/changelog

@@ -1,4 +1,4 @@
-ngcp-asterisk (1.4.24.1-rsp+svn4100.6) unstable; urgency=medium
+ngcp-asterisk (1.4.24.1rsp+svn4100.6) unstable; urgency=medium
 
   * rebuild with newer lib versions.