change more instances of mistyped `erl_first_modules` to

`erl_first_files`

fixes #99

src/rebar_prv_common_test.erl

@@ -310,7 +310,7 @@ add_test_dir(Opts, InDirs) ->
 first_files(State) ->
     BaseFirst = rebar_state:get(State, erl_first_files, []),
     CTFirst = rebar_state:get(State, common_test_first_files, []),
-    rebar_state:set(State, erl_first_modules, BaseFirst ++ CTFirst).
+    rebar_state:set(State, erl_first_files, BaseFirst ++ CTFirst).
 
 resolve_ct_opts(State, CmdLineOpts, OutDir) ->
     CTOpts = rebar_state:get(State, common_test_opts, []),

src/rebar_prv_eunit.erl

@@ -149,7 +149,7 @@ test_defined([]) -> false.
 first_files(State) ->
     BaseFirst = rebar_state:get(State, erl_first_files, []),
     EUnitFirst = rebar_state:get(State, eunit_first_files, []),
-    rebar_state:set(State, erl_first_modules, BaseFirst ++ EUnitFirst).
+    rebar_state:set(State, erl_first_files, BaseFirst ++ EUnitFirst).
 
 resolve_eunit_opts(State, Opts) ->
     EUnitOpts = rebar_state:get(State, eunit_opts, []),