[SPARK-17320] add build_profile_flags entry to mesos build module

## What changes were proposed in this pull request?

add build_profile_flags entry to mesos build module

## How was this patch tested?

unit tests

Author: Michael Gummelt <mgummelt@mesosphere.io>

Closes #14885 from mgummelt/mesos-profile.

dev/sparktestsupport/modules.py

@@ -462,6 +462,7 @@ mesos = Module(
     name="mesos",
     dependencies=[],
     source_file_regexes=["mesos/"],
+    build_profile_flags=["-Pmesos"],
     sbt_test_goals=["mesos/test"]
 )