InitializeParams should include an empty ClientCapabilities (eclipse-che#2466)

The protocol specifies that the InitializeParams object contains a
capabilities property. Eclipse Che does not define it, so there are
language servers that fails to initialize because of this.

Signed-off-by: Kaloyan Raev <kaloyan.r@zend.com>

Author: kaloyan-raev

plugins/plugin-languageserver/che-plugin-languageserver-server/src/main/java/org/eclipse/che/plugin/languageserver/server/registry/ServerInitializerImpl.java

@@ -12,6 +12,7 @@
 
 import io.typefox.lsapi.InitializeResult;
 import io.typefox.lsapi.ServerCapabilities;
+import io.typefox.lsapi.impl.ClientCapabilitiesImpl;
 import io.typefox.lsapi.impl.InitializeParamsImpl;
 import io.typefox.lsapi.services.LanguageServer;
 
@@ -151,6 +152,7 @@ protected InitializeParamsImpl prepareInitializeParams(String projectPath) {
         InitializeParamsImpl initializeParams = new InitializeParamsImpl();
         initializeParams.setProcessId(PROCESS_ID);
         initializeParams.setRootPath(projectPath);
+        initializeParams.setCapabilities(new ClientCapabilitiesImpl());
         initializeParams.setClientName(CLIENT_NAME);
         return initializeParams;
     }