log_manager: Remove designated initializers

These aren't allowed until -std=c++2a.

Change-Id: If0e829170bf01f330f54f4d5fbe892078109049c
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/log_manager.cpp b/log_manager.cpp
index 9e10d75..67f6e10 100644
--- a/log_manager.cpp
+++ b/log_manager.cpp
@@ -723,9 +723,9 @@
 
         // Let's wait until inotify reports an event
         struct pollfd fds = {
-            .fd = fd,
-            .events = POLLIN,
-            .revents = 0,
+            fd,
+            POLLIN,
+            0,
         };
         constexpr auto pollTimeout = 5; // 5 seconds
         rc = poll(&fds, 1, pollTimeout * 1000);