Merge pull request syslog-ng#3771 from mitzkia/gdb_tool_to_kira_image

Dbld/images/Kira: Add gdb tool to kira image

Author: Gábor Nagy

dbld/packages.manifest

@@ -117,6 +117,7 @@ libmongoc-dev               [debian, ubuntu-xenial]
 # Tools required to run @kira-syslogng, our testbot.
 #############################################################################
 
+gdb                             [kira]
 faketime                        [kira]
 libdbd-mysql                    [kira]
 lsb-release                     [kira]