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/liblog/logger_write.cpp b/liblog/logger_write.cpp
index fbe6874..af8cb2d 100644
--- a/liblog/logger_write.cpp
+++ b/liblog/logger_write.cpp
@@ -33,6 +33,7 @@
 #include "config_write.h"
 #include "log_portability.h"
 #include "logger.h"
+#include "uio.h"
 
 #define LOG_BUF_SIZE 1024
 
@@ -524,11 +525,8 @@
 
   // Log assertion failures to stderr for the benefit of "adb shell" users
   // and gtests (http://b/23675822).
-  struct iovec iov[2] = {
-      {buf, strlen(buf)},
-      {(char*)"\n", 1},
-  };
-  TEMP_FAILURE_RETRY(writev(2, iov, 2));
+  TEMP_FAILURE_RETRY(write(2, buf, strlen(buf)));
+  TEMP_FAILURE_RETRY(write(2, "\n", 1));
 
   __android_log_write(ANDROID_LOG_FATAL, tag, buf);
   abort(); /* abort so we have a chance to debug the situation */