media-libs/openslide: DEPEND 'virtual/jpeg' instead of 'media-libs/jpeg:0'

[Marco Emilio "sphakka" Poleggi]

[Ge/Fun]too has moved to libjpeg-turbo, usually selected by default virtual. This fixes

# diff -u openslide-3.4.1.ebuild openslide-3.4.1-r1.ebuild
--- openslide-3.4.1.ebuild	2019-01-02 02:22:34.000000000 +0100
+++ openslide-3.4.1-r1.ebuild	2019-07-19 16:00:11.125712865 +0200
@@ -14,7 +14,7 @@
 
 IUSE="doc"
 DEPEND="
-	media-libs/jpeg:0
+	virtual/jpeg
 	media-libs/openjpeg:2
 	media-libs/tiff:0
 	virtual/libc

It works on my Funtoo installation :-)