Unit tests will fail to compile without EQC

[rzezeski]

If a user doesn't have EQC installed then the unit tests will fail to compile. That is, make test will fail. This applies to all our community users as well as test machines without EQC installed.

==> riak_dt (compile)
Compiled src/riak_dt.erl
Compiled src/orset_bm.erl
src/riak_dt_enable_flag.erl:35: can't find include lib "eqc/include/eqc.hrl"
ERROR: compile failed while processing /Users/rzezeski/work/riak_kv/deps/riak_dt: rebar_abort
make: *** [test-compile] Error 1

[seancribbs]

Addressed by #787