Handle file comment

File comment doesn't have line number and its location is at line 0.

Currently the code will have NPE when there's a file comment in the
review.

Change-Id: I577f243572d91837529bbc55aeb3f290496f5e4e
Signed-off-by: Ardo Septama <aseptama@gmail.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/importer/ReplayInlineCommentsStep.java b/src/main/java/com/googlesource/gerrit/plugins/importer/ReplayInlineCommentsStep.java
index 1de5473..8fabda0 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/importer/ReplayInlineCommentsStep.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/importer/ReplayInlineCommentsStep.java
@@ -210,7 +210,7 @@
             c.range.endCharacter));
         e.lineNbr = c.range.endLine;
       } else {
-        e.lineNbr = c.line;
+        e.lineNbr = c.line == null ? 0 : c.line;
       }
       ups.add(e);
     }