Fix copying text in Internet Explorer

The '-ms-user-select' css property doesn't support 'initial', so use
'text' instead.

Also add the 'user-select' css property for browsers that don't prefix
their css properties.

Bug: Issue 4647
Change-Id: Ife1ebcc8f4aadddb80de18515065c13339d54f64
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.css b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.css
index e72c840..f4f1e83 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.css
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.css
@@ -63,7 +63,8 @@
   -webkit-user-select: initial;
   -khtml-user-select: initial;
   -moz-user-select: text;
-  -ms-user-select: initial;
+  -ms-user-select: text;
+  user-select: initial;
 }
 
 .commentBox {