logd: drop libminijail dependency

Use libcap instead of libminijail.  Set CAP_SETGID before setgroups,
then clear it afterwards.

Test: gTest logd-unit-tests, liblog-unit-tests and logcat-unit-tests
Bug: 32450474
Change-Id: I2ed027fd5efd95f76b1dd4c5791bae5f2ea94c28
diff --git a/logd/Android.mk b/logd/Android.mk
index 81637d2..7fe48d7 100644
--- a/logd/Android.mk
+++ b/logd/Android.mk
@@ -29,7 +29,7 @@
     libcutils \
     libbase \
     libpackagelistparser \
-    libminijail
+    libcap
 
 # This is what we want to do:
 #  event_logtags = $(shell \