meta-phosphor: libvncserver: pin PACKAGECONFIG

PACKAGECONFIGs are added upstream frequently.  Avoid new implicit
dependencies by pinning to the exact options required by OpenBMC today.

Change-Id: I600f07d84864187410e8cc604365360e9986be0b
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/recipes-graphics/libvncserver/libvncserver_%.bbappend b/recipes-graphics/libvncserver/libvncserver_%.bbappend
index 849255a..fa15047 100644
--- a/recipes-graphics/libvncserver/libvncserver_%.bbappend
+++ b/recipes-graphics/libvncserver/libvncserver_%.bbappend
@@ -1,2 +1 @@
-PACKAGECONFIG_append = " openssl"
-PACKAGECONFIG_remove = "gcrypt gnutls png sdl"
+PACKAGECONFIG = "jpeg lzo systemd zlib openssl"