Remove libsigchain from LD_PRELOADs

Bug: 15345057
Bug: 15426766

(cherry picked from commit c9f9f35efa43b3ac75b1a7e76fe1071a2e9d52ea)

Change-Id: If54e1aeaa1e2abe061ac19666af4f4e058b81df2
diff --git a/rootdir/init.environ.rc.in b/rootdir/init.environ.rc.in
index 67222d7..30bef46 100644
--- a/rootdir/init.environ.rc.in
+++ b/rootdir/init.environ.rc.in
@@ -10,4 +10,3 @@
     export LOOP_MOUNTPOINT /mnt/obb
     export BOOTCLASSPATH %BOOTCLASSPATH%
     export SYSTEMSERVERCLASSPATH %SYSTEMSERVERCLASSPATH%
-    export LD_PRELOAD libsigchain.so