Update git submodules

Update git submodules

* Update extensions/CategoryTree from branch 'REL1_31'
  to a1717183d7a263ad2a109a1891ac430f1e604c02
  - Change 'title' attributes to links to use full page name

    This changes the title attribute on the link generated in the
    CategoryTree. The only effect is additional information about the
    link target that may be truncated by 'hideprefix' or CSS overflow,
    will now still be accessible in another way.

    Change-Id: I4f07fa88f0a528634e9bf3c504e84fb4bf55e3bf
    (cherry picked from commit 1dfe6ca618afd5b85631417c10772591de02043a)