Merge branch 'dl/submodule-set-branch'

"git submodule" learns "set-branch" subcommand that allows the
submodule.*.branch settings to be modified.

* dl/submodule-set-branch:
  submodule: teach set-branch subcommand
  submodule--helper: teach config subcommand --unset
  git-submodule.txt: "--branch <branch>" option defaults to 'master'

diff --cc Documentation/git-submodule.txt
Simple merge

diff --cc builtin/submodule--helper.c
Simple merge

diff --cc contrib/completion/git-completion.bash
index 42a3c8e52417d42a255c68a4f6f24a1518bb3404,8b3b5a9d34590fbf025753d87c5a69ec77945239..3eefbabdb12266cd94729bdeacc088785d917967
--- 1/contrib/completion/git-completion.bash
--- 2/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@@ -2611,7 -2573,7 +2611,7 @@@ _git_submodule (
  {
        __git_has_doubledash && return
  
-       local subcommands="add status init deinit update summary foreach sync absorbgitdirs"
 -      local subcommands="add status init deinit update set-branch summary foreach sync"
++      local subcommands="add status init deinit update set-branch summary foreach sync absorbgitdirs"
        local subcommand="$(__git_find_on_cmdline "$subcommands")"
        if [ -z "$subcommand" ]; then
                case "$cur" in

diff --cc git-submodule.sh
Simple merge