Update git submodules

* Update tools/repohooks from branch 'master'
  to 2e1406dfa9a57fab579ba4862f679a407e6349ac
  - git: use "git rev-list" to get a revision listing
    
    As a lower-level plumbing command designed for scripting, this can be
    counted on to behave simply and predictably over time.
    
    Change-Id: I628727686898a3fa5441a2dc58f9edb867d2aec7
    
1 file changed