Have vold grab a partial wakelock when encrypting

The Progress bar UI grabs a full wakelock when encrypting, but we've seen
a case where it looks like the progress bar UI crashes, and the wakelock is
lost, and then all hell breaks loose.  The enablecrypto command has a lot of
work to do, and it will take some time, so it should grab a wakelock to
ensure it can finish without being interrupted and put to sleep.

It grabs a partial wake lock, as it doesn't need the screen to be on to do
its work.  If the UI wants to keep it on, it should also grab a full wakelock,
which it does.  If the UI crashes, the screen may turn off, but the encryption
will keep going, and vold will reboot the device when it's done.

Change-Id: I51d3a72b8c77383044a3facb1604c1ee510733ae
diff --git a/Android.mk b/Android.mk
index 3b96aab..48df613 100644
--- a/Android.mk
+++ b/Android.mk
@@ -33,6 +33,7 @@
 	libsysutils \
 	libcutils \
 	libdiskconfig \
+	libhardware_legacy \
 	libcrypto
 
 include $(CLEAR_VARS)