Another bug fix for line numbers. Line uses signed in advancing.

While addres (Dex PC) uses unsigned in advancing, line number uses
signed. Now 007-exceptions passes.

Change-Id: Ic65cd5093274c6b4d0e9949e5ea50efcdaf71322
diff --git a/src/dex_file.cc b/src/dex_file.cc
index 0a18f11..57ff2e3 100644
--- a/src/dex_file.cc
+++ b/src/dex_file.cc
@@ -686,7 +686,7 @@
         break;
 
       case DBG_ADVANCE_LINE:
-        line += DecodeUnsignedLeb128(&stream);
+        line += DecodeSignedLeb128(&stream);
         break;
 
       case DBG_START_LOCAL: