ls-files and read-tree need core.filemode

Hi,

ls-files.c and read-tree.c miss the default configuration, in
particular the filemode=false part.
The recent +x bit flip made me notice that, because git-merge refused
to merge anything saying that git-pull.sh is not up to date.

As usual, sorry for attachments.

Public apology and brown paper bag.  My patch
accidentally twiddled the mode on git-pull.sh:

    Signed-off-by: Jon Loeliger [off-list ref]

    ---

     Documentation/git-pull.txt        |   17 +++++++----------
     Documentation/merge-options.txt   |   16 ++++++++++++++++
     Documentation/merge-pull-opts.txt |   14 --------------
     git-format-patch.sh               |    4 ++++
     git-pull.sh                       |   12 +++++++++++-
     9 files changed, 70 insertions(+), 48 deletions(-)
     create mode 100644 Documentation/fetch-options.txt
     create mode 100644 Documentation/merge-options.txt
     delete mode 100644 Documentation/merge-pull-opts.txt
     mode change 100755 => 100644 git-pull.sh