Account for different diretory structure in repo that provided the patch

cve-2015-4645.patch

@@ -1,7 +1,7 @@
-diff --git a/unsquash-4.c b/unsquash-4.c
+diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
 index ecdaac796f09..2c0cf63daf67 100644
---- a/unsquash-4.c
-+++ b/unsquash-4.c
+--- a/squashfs-tools/unsquash-4.c
++++ b/squashfs-tools/unsquash-4.c
 @@ -31,9 +31,9 @@ static unsigned int *id_table;
  int read_fragment_table_4(long long *directory_table_end)
  {