[shotwell] flatpak: Fix build with SDK 3.30

[Jens Georg <jensgeorg src gnome org>]

commit 5864c0fc60e9692d8ad9983646b119792776ed0f
Author: Jens Georg <mail jensge org>
Date:   Tue Oct 2 12:25:02 2018 +0200

    flatpak: Fix build with SDK 3.30
    
    There seems to be an issue with either CMake or pkg-config and lib64

 flatpak/org.gnome.Shotwell.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/flatpak/org.gnome.Shotwell.json b/flatpak/org.gnome.Shotwell.json
index aab084c7..f6dd7ff3 100644
--- a/flatpak/org.gnome.Shotwell.json
+++ b/flatpak/org.gnome.Shotwell.json
@@ -100,6 +100,7 @@
             "name": "exiv2",
             "cleanup": [ "/bin" ],
             "buildsystem": "cmake",
+            "config-opts" : ["-DCMAKE_INSTALL_LIBDIR=lib"],
             "sources": [
                 {
                     "type": "git",
@@ -147,7 +148,7 @@
             "buildsystem": "cmake",
             "builddir": true,
             "cleanup" : ["/share/OpenCV/*.cmake", "/share/OpenCV/*.supp"],
-            "config-opts" : ["-DBUILD_TESTS=OFF", "-DBUILD_EXAMPLES=OFF", "-DBUILD_PERF_TESTS=OFF", 
"-DWITH_FFMPEG=OFF", "-DWITH_GTK=OFF", "-DWITH_GSTREAMER=OFF", "-DBUILD_opencv_apps=OFF"],
+            "config-opts" : ["-DBUILD_TESTS=OFF", "-DBUILD_EXAMPLES=OFF", "-DBUILD_PERF_TESTS=OFF", 
"-DWITH_FFMPEG=OFF", "-DWITH_GTK=OFF", "-DWITH_GSTREAMER=OFF", "-DBUILD_opencv_apps=OFF", 
"-DCMAKE_INSTALL_LIBDIR=lib"],
             "sources": [
                 {
                     "type": "git",