Use fcntl.h instead of sys/fcntl.h

Use the standard fcntl.h instead of the implementation detail sys/fcntl.h
to fix building against musl libc.

Bug: 190084016
Test: m USE_HOST_MUSL=true host-native
Change-Id: I73df399af21309e1abc2277e9687bba7a857d4fc
diff --git a/aosp/update_attempter_android_unittest.cc b/aosp/update_attempter_android_unittest.cc
index a3f25b9..458c224 100644
--- a/aosp/update_attempter_android_unittest.cc
+++ b/aosp/update_attempter_android_unittest.cc
@@ -20,7 +20,7 @@
 #include <string>
 #include <utility>
 
-#include <sys/fcntl.h>
+#include <fcntl.h>
 #include <sys/sendfile.h>
 #include <unistd.h>