Add ro.bootimage.* property contexts

In addition, allow shell to read this property.

Test: getprop -Z
Test: cts-tradefed run cts -m CtsGestureTestCases
      and check /sdcard/device-info-files/PropertyDeviceInfo.deviceinfo.json

Bug: 169169031
Change-Id: Ib71b01bac326354696e159129f9dea4c2e918c51
diff --git a/private/shell.te b/private/shell.te
index dff6a9f..c926283 100644
--- a/private/shell.te
+++ b/private/shell.te
@@ -141,6 +141,9 @@
 # Allow reading the outcome of perf_event_open LSM support test for CTS.
 get_prop(shell, init_perf_lsm_hooks_prop)
 
+# Allow shell to read boot image timestamps and fingerprints.
+get_prop(shell, build_bootimage_prop)
+
 userdebug_or_eng(`set_prop(shell, persist_debug_prop)')
 
 # Allow to issue control commands to profcollectd binder service.