Update git submodules

Update git submodules

* Update docs/submodules/apex from branch 'master'
  - Merge "Add collectd-snmp and collect-rdt installation. Use the Intel RDT version which is current (the version in the package set specified by the latest.properties file)."
  - Add collectd-snmp and collect-rdt installation.
    Use the Intel RDT version which is current (the version in the package set specified by the latest.properties file).

    Change-Id: I3f176572edaa5d3df5b3cc31b39253025d81e808
    Signed-off-by: jhinman1 <john.hinman@intel.com>