Remove liblog/uio.c and <log/uio.h>

readv() isn't used by anyone, writev() has one easily replaced user.
uio.h can be left as a private header for windows compatibility with
struct iovec.

Test: build
Change-Id: I33d4c6bdee6fd818271f78ae06abdd2aa09430f2
diff --git a/libstats/statsd_writer.c b/libstats/statsd_writer.c
index f00fc2d..f5be95c 100644
--- a/libstats/statsd_writer.c
+++ b/libstats/statsd_writer.c
@@ -31,6 +31,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <sys/un.h>
 #include <time.h>
 #include <unistd.h>