Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 6387c2174b5fe53dda56ebaf7b51b4ad6e8239a4
  - Merge "All extendable enums should be serializable"
  - All extendable enums should be serializable
    
    marking items as transient causes them to be lost
    
    Issue-ID: SO-2217
    Signed-off-by: Benjamin, Max (mb388a) <mb388a@att.com>
    Change-Id: If66f9034b67f94c8122875ef915043525fb9bdb7
    
1 file changed