tools: Make gen-changelog.sh print more lines from the tag annotation.

tools/gen-changelog.sh

@@ -8,5 +8,5 @@ for t in $(git tag | grep -v v1.0-rc1 | sort -rV); do
     echo ''
     git show -s --format=%cD `git rev-list $t --max-count=1`
     echo ''
-    git tag -l $t -n99
+    git tag -l $t -n9999
 done