[lmi] Avoiding a git-checkout failure

[Greg Chicares]

Vadim--On a machine in the office, yesterday we observed:

[here, PWD is /srv/cache_for_lmi/vcs/wxWidgets]
  git checkout "$wx_commit_sha"
  + git checkout 6cdaedd42ba59331b3dc4ead50e0bac76ae14c19
  error: Your local changes to the following files would be overwritten by 
checkout:
        .gitignore
        .mailmap
        .travis.yml
        CMakeLists.txt
        Makefile.in
[...snip long list...]
        build/msw/wx_vc8_wxtiff.vcproj
        build/msw/wx_vc8_wxzlib.vcproj
        build/msw/wx_vc8_xml.vcproj
        build/msw/wx_vc8_xrc.vc
  Please move or remove them before you switch branches.
  Aborting

and a similar failure with wxPdfDoc.

I'd guess this means that 'configure' had been run in this cache
directory at some time, perhaps years ago.

The patch below gets us past these failures, but before applying
it I'd like to ask whether you have any objection. Any local
modifications in our cache directory are sure to be unintentional.
OTOH, wx developers regularly have local modifications, but most
likely not in a /srv/cache_for_lmi/ directory.

I suppose we could do this instead:
  git stash --all
but running the script would still make silent changes in any
local work, so I'm not sure that's any better.

---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---8<---
diff --git a/install_wx.sh b/install_wx.sh
index 3b0af548..f858d533 100755
--- a/install_wx.sh
+++ b/install_wx.sh
@@ -75,6 +75,8 @@ then
     git fetch origin
 fi
 
+# Reset in case git-checkout would fail.
+git reset --hard
 git checkout "$wx_commit_sha"
 
 # Get any new submodules that may have been added, even if nested.
diff --git a/install_wxpdfdoc.sh b/install_wxpdfdoc.sh
index 11068cdc..37867de9 100755
--- a/install_wxpdfdoc.sh
+++ b/install_wxpdfdoc.sh
@@ -75,6 +75,8 @@ then
     git fetch origin
 fi
 
+# Reset in case git-checkout would fail.
+git reset --hard
 git checkout "$wxpdfdoc_commit_sha"
 
 build_type=$("$proxy_wxpdfdoc_dir"/admin/build-aux/config.guess)
--->8--->8--->8--->8--->8--->8--->8--->8--->8--->8--->8--->8--->8---