[PATCH] vcs_info: use `--ignore-submodules=dirty` with diff/diff-index

[Daniel Hahler <dhahler@gmail.com>]

This will detect changes to submodules from the superproject's
perspective, e.g. after `git rm submodule`.

>From GIT-DIFF-INDEX(1)/GIT-DIFF(1):

    Using "dirty" ignores all changes to the work tree of submodules,
    only changes to the commits stored in the superproject are shown
    (this was the behavior until 1.7.0).
---
 Functions/VCS_Info/Backends/VCS_INFO_get_data_git | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Functions/VCS_Info/Backends/VCS_INFO_get_data_git b/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
index c243bf7..ee50be6 100644
--- a/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
+++ b/Functions/VCS_Info/Backends/VCS_INFO_get_data_git
@@ -176,17 +176,17 @@ if (( querystaged || queryunstaged )) && \
    [[ "$(${vcs_comm[cmd]} rev-parse --is-inside-work-tree 2> /dev/null)" == 'true' ]] ; then
     # Default: off - these are potentially expensive on big repositories
     if (( queryunstaged )) ; then
-        ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules --quiet --exit-code ||
+        ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules=dirty --quiet --exit-code ||
             gitunstaged=1
     fi
     if (( querystaged )) ; then
         if ${vcs_comm[cmd]} rev-parse --quiet --verify HEAD &> /dev/null ; then
-            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules HEAD 2> /dev/null
+            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules=dirty HEAD 2> /dev/null
             (( $? && $? != 128 )) && gitstaged=1
         else
             # empty repository (no commits yet)
             # 4b825dc642cb6eb9a060e54bf8d69288fbee4904 is the git empty tree.
-            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules 4b825dc642cb6eb9a060e54bf8d69288fbee4904 2>/dev/null
+            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules=dirty 4b825dc642cb6eb9a060e54bf8d69288fbee4904 2>/dev/null
             (( $? && $? != 128 )) && gitstaged=1
         fi
     fi
--
2.1.0