printing: Install printbackends

Add "install : true" for each printbackend so that they are installed.

https://bugzilla.gnome.org/show_bug.cgi?id=789185

modules/printbackends/cloudprint/meson.build

@@ -7,4 +7,5 @@ shared_module('printbackend-cloudprint',
                 '-DGTK_DISABLE_DEPRECATION_WARNINGS',
               ],
               dependencies: [ libgtk_dep, rest_dep, json_glib_dep ],
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)

modules/printbackends/cups/meson.build

@@ -18,4 +18,5 @@ shared_module('printbackend-cups',
                 '-DGTK_PRINT_BACKEND_ENABLE_UNSUPPORTED',
               ],
               dependencies: [libgtk_dep, libcups, colord_dep],
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)

modules/printbackends/file/meson.build

@@ -6,4 +6,5 @@ shared_module('printbackend-file',
                 '-DGTK_PRINT_BACKEND_ENABLE_UNSUPPORTED',
               ],
               dependencies: libgtk_dep,
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)

modules/printbackends/lpr/meson.build

@@ -6,4 +6,5 @@ shared_module('printbackend-lpr',
                 '-DGTK_PRINT_BACKEND_ENABLE_UNSUPPORTED',
               ],
               dependencies: libgtk_dep,
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)

modules/printbackends/papi/meson.build

@@ -6,4 +6,5 @@ shared_module('printbackend-papi',
                 '-DGTK_PRINT_BACKEND_ENABLE_UNSUPPORTED',
               ],
               dependencies: [libgtk_dep, libpapi],
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)

modules/printbackends/test/meson.build

@@ -6,4 +6,5 @@ shared_module('printbackend-test',
                 '-DGTK_PRINT_BACKEND_ENABLE_UNSUPPORTED',
               ],
               dependencies: libgtk_dep,
-              install_dir: printbackends_install_dir)
+              install_dir: printbackends_install_dir,
+              install : true)