Remove workaround regarding newlines on GWT UI

The GWT UI always appended a newline character to the diff content it
received from the server, no matter whether the file contained a
newline at the end or not. Since the server now sends an empty string
if there is a newline at the end, we don't need the workaround anymore.

Change-Id: I0da144366d3245e88e4e5529828ac1f900f46fd3

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffInfo.java

diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffInfo.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffInfo.java
index cf40762..d942c2e 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffInfo.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffInfo.java
@@ -137,7 +137,10 @@
 
   private static void append(StringBuilder s, JsArrayString lines) {
     for (int i = 0; i < lines.length(); i++) {
-      s.append(lines.get(i)).append('\n');
+      if (s.length() > 0) {
+        s.append('\n');
+      }
+      s.append(lines.get(i));
     }
   }