digest: Remove empty directory.

libphobos/ChangeLog:

2018-12-14  Iain Buclaw  <ibuclaw@gdcproject.org>

	* src/std/internal/digest: Remove empty directory.

From-SVN: r267138

libphobos/ChangeLog

+2018-12-14  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	* src/std/internal/digest: Remove empty directory.
+
 2018-12-08  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* Makefile.am (AM_MAKEFLAGS): Pass CCASFLAGS, GDCFLAGS.