[geary] Use meson's standard approach to finding the messaging-menu library

[Michael Gratton <mjog src gnome org>]

commit 3a9b2855ed9ab9928d0d3a6ba9cee78b6feb8666
Author: Michael Gratton <mike vee net>
Date:   Wed Feb 27 12:06:12 2019 +1100

    Use meson's standard approach to finding the messaging-menu library
    
    Fixes FTB on master.

 meson.build            | 2 +-
 src/client/meson.build | 6 ------
 2 files changed, 1 insertion(+), 7 deletions(-)
---
diff --git a/meson.build b/meson.build
index ff871e3a..cf57cfca 100644
--- a/meson.build
+++ b/meson.build
@@ -102,8 +102,8 @@ endif
 # Optional dependencies
 appstream_util = find_program('appstream-util', required: false)
 desktop_file_validate = find_program('desktop-file-validate', required: false)
+libmessagingmenu = dependency('libmessaging-menu', version: '>= 12.10', required: false)
 libunity = dependency('unity', version: '>= 5.12.0', required: false)
-libmessagingmenu = meson.get_compiler('c').find_library('libmessaging-menu', required: false)
 
 # Ensure SQLite was built correctly
 if not cc.has_header_symbol('sqlite3.h', 'SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER', dependencies: sqlite)
diff --git a/src/client/meson.build b/src/client/meson.build
index 72c8125b..3d6b9fb9 100644
--- a/src/client/meson.build
+++ b/src/client/meson.build
@@ -130,13 +130,7 @@ geary_client_dependencies = [
 geary_client_vala_options = geary_vala_options
 
 if libmessagingmenu.found()
-  messagingmenu_vapi = meson.get_compiler('vala').find_library(
-      'MessagingMenu-1.0',
-      dirs: '/usr/share/vala/vapi',
-      required: true
-  )
   geary_client_dependencies += libmessagingmenu
-  geary_client_dependencies += messagingmenu_vapi
   geary_client_vala_options += ['-D', 'HAVE_LIBMESSAGINGMENU']
 endif
 if libunity.found()