Clang: Send document revision with the completion request

The sent text should always accompanied by the document revision to avoid
useless the reparsing of the translation unit.

Change-Id: I4af50f277f9352f4af0cdda8a32ad76c44c1935f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp

@@ -677,7 +677,8 @@ void ClangCompletionAssistProcessor::sendFileContent(const QString &projectPartI
     ipcCommunicator.registerFilesForCodeCompletion({{m_interface->fileName(),
                                                      projectPartId,
                                                      Utf8String::fromByteArray(info.unsavedContent),
-                                                     info.isDocumentModified}});
+                                                     info.isDocumentModified,
+                                                     uint(m_interface->textDocument()->revision())}});
 }
 
 void ClangCompletionAssistProcessor::sendCompletionRequest(int position,