Throw an exception if a raw message has been deleted.

...ava/org/briarproject/bramble/api/client/ClientHelper.java

...va/org/briarproject/bramble/api/db/DatabaseComponent.java

.../briarproject/bramble/api/db/MessageDeletedException.java

...ava/org/briarproject/bramble/client/ClientHelperImpl.java

...e/src/main/java/org/briarproject/bramble/db/Database.java

...va/org/briarproject/bramble/db/DatabaseComponentImpl.java

...c/main/java/org/briarproject/bramble/db/JdbcDatabase.java

...ject/bramble/properties/TransportPropertyManagerImpl.java

.../org/briarproject/bramble/sync/ValidationManagerImpl.java

...oject/bramble/versioning/ClientVersioningManagerImpl.java

...st/java/org/briarproject/bramble/db/JdbcDatabaseTest.java

...ain/java/org/briarproject/briar/blog/BlogManagerImpl.java

...n/java/org/briarproject/briar/forum/ForumManagerImpl.java

...arproject/briar/introduction/IntroductionManagerImpl.java

...rg/briarproject/briar/messaging/MessagingManagerImpl.java

...arproject/briar/privategroup/PrivateGroupManagerImpl.java

...ject/briar/privategroup/invitation/MessageParserImpl.java

...ava/org/briarproject/briar/sharing/MessageParserImpl.java