Handle the branch.<name>.rebase value 'interactive'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Documentation/config.txt

@@ -771,6 +771,7 @@ branch.<name>.rebase::
 	instead of merging the default branch from the default remote when
 	"git pull" is run. See "pull.rebase" for doing this in a non
 	branch-specific manner.
+	When the value is `interactive`, the rebase is run in interactive mode.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]

git-pull.sh

@@ -44,7 +44,15 @@ merge_args= edit=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short="${curr_branch#refs/heads/}"
 rebase_options=
-rebase=$(git config --bool branch.$curr_branch_short.rebase)
+case "$(git config branch.$curr_branch_short.rebase)" in
+interactive)
+	rebase_options=-i
+	rebase=true
+	;;
+*)
+	rebase=$(git config --bool branch.$curr_branch_short.rebase)
+	;;
+esac
 if test -z "$rebase"
 then
 	rebase=$(git config --bool pull.rebase)