Ensure BasicDebugger works for newer Ruby versions.

Sending non String to Kernel.eval doesn't work so ensure it is converted
beforehand.

See-also: https://bugzilla.redhat.com/show_bug.cgi?id=1319761

Change-Id: I7dfbf2e2f4b7064d15e860d479c860c4c1ef8102
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
diff --git a/plugins/org.eclipse.dltk.ruby.basicdebugger/debugger/basic/BasicContext.rb b/plugins/org.eclipse.dltk.ruby.basicdebugger/debugger/basic/BasicContext.rb
index f4dde95..3e5bb1d 100644
--- a/plugins/org.eclipse.dltk.ruby.basicdebugger/debugger/basic/BasicContext.rb
+++ b/plugins/org.eclipse.dltk.ruby.basicdebugger/debugger/basic/BasicContext.rb
@@ -1,3 +1,12 @@
+###############################################################################
+# Copyright (c) 2005, 2016 IBM Corporation and others.
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Eclipse Public License v1.0
+# which accompanies this distribution, and is available at
+# http://www.eclipse.org/legal/epl-v10.html
+#
+###############################################################################
+
 require 'monitor'
 require 'common/Logger'
 require 'debugger/AbstractContext'
@@ -95,7 +104,7 @@
             end
             binding = frame[ :binding ]
             info = frame[ :info ]
-            Kernel.eval(text, binding, info.file, info.line)            
+            Kernel.eval(text.to_s, binding, info.file, info.line)            
         end
                     
         # Stack depth