fake_log_device: long lived allocations

Use static space for long lived allocations as they
will appear to act like a memory leak. Resort to a
larger on-stack iovec to reduce the chances of an
allocation. Fix bug in writer where not enough size
was available for "security" buffer name. Minor
transitions to more consistent coding style.

Bug: 27107691
Change-Id: I68c918e7b916b1ae3b04829d48b3eddaa0a7e739
diff --git a/liblog/logd_write.c b/liblog/logd_write.c
index 4946073..b173d1a 100644
--- a/liblog/logd_write.c
+++ b/liblog/logd_write.c
@@ -125,7 +125,7 @@
 
 #if FAKE_LOG_DEVICE
     for (i = 0; i < LOG_ID_MAX; i++) {
-        char buf[sizeof("/dev/log_system")];
+        char buf[sizeof("/dev/log_security")];
         snprintf(buf, sizeof(buf), "/dev/log_%s", android_log_id_to_name(i));
         log_fds[i] = fakeLogOpen(buf, O_WRONLY);
     }