Revert "Eolian: fix eolian helper for windows."

This reverts commit 60b473d949.

It breaks our mingw cross build setup we are using on jenkins. In summary it
silently fails to use eolian_gen.exe while it should use the linux native
eolian_gen and thus does not generate the c and h files from the eo ones.

See the ml for details or look at the error here:
https://build.enlightenment.org/job/changely_efl_mingw_x86_64/2115/console

src/Makefile_Eolian_Helper.am

@@ -1,6 +1,6 @@
 if HAVE_EOLIAN_GEN
-EOLIAN_GEN = @eolian_gen@${EXEEXT}
-_EOLIAN_GEN_DEP = @eolian_gen@${EXEEXT}
+EOLIAN_GEN = @eolian_gen@
+_EOLIAN_GEN_DEP = @eolian_gen@
 else
 EOLIAN_GEN = EFL_RUN_IN_TREE=1 $(top_builddir)/src/bin/eolian/eolian_gen${EXEEXT}
 _EOLIAN_GEN_DEP = bin/eolian/eolian_gen${EXEEXT}