Surface SCons cache hit statistics to Splunk

We create a file on every server compile task that contains cache hit data for the SCons cache.

It would be nice to capture that data to somewhere we could use to monitor the effectiveness of the cache(s).

You can see an example file here: https://s3.amazonaws.com/mciuploads/mongodb-mongo-master/enterprise-rhel-62-64-bit/80e0497ebaaaf87707239f661cac2ab99ca9a88c/scons-cache-mongodb_mongo_master_enterprise_rhel_62_64_bit_80e0497ebaaaf87707239f661cac2ab99ca9a88c_19_11_04_17_32_44-0.log