otautil: roots.cpp no longer needs 'mounts.h'.

Commit 0f339e27bb753b0dafb17a315fa4b029ba31aa28 moved part of the mounts
implementation into libfs_mgr. As a result, otautil/roots.cpp no longer
depends on anything in the local otautil/mounts.h.

Test: mmma bootable/recovery
Change-Id: If16c3e19a62933358fb0002a10e8556a99f9d29a
diff --git a/otautil/roots.cpp b/otautil/roots.cpp
index 4315517..aa7809b 100644
--- a/otautil/roots.cpp
+++ b/otautil/roots.cpp
@@ -42,7 +42,6 @@
 #include <fs_mgr/roots.h>
 #include <fs_mgr_dm_linear.h>
 
-#include "otautil/mounts.h"
 #include "otautil/sysutil.h"
 
 using android::fs_mgr::Fstab;