NetBpfLoad: do not log bpfGetFdMapId() failures on 4.9

This is entirely expected due to lack of implementation in <4.14.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ifebe6843dc77b1b9a506c61239dcebe7262d0869
diff --git a/bpf/loader/NetBpfLoad.cpp b/bpf/loader/NetBpfLoad.cpp
index 59712b1..07be8c6 100644
--- a/bpf/loader/NetBpfLoad.cpp
+++ b/bpf/loader/NetBpfLoad.cpp
@@ -839,7 +839,8 @@
 
         int mapId = bpfGetFdMapId(fd);
         if (mapId == -1) {
-            ALOGE("bpfGetFdMapId failed, ret: %d [%d]", mapId, errno);
+            if (isAtLeastKernelVersion(4, 14, 0))
+                ALOGE("bpfGetFdMapId failed, ret: %d [%d]", mapId, errno);
         } else {
             ALOGI("map %s id %d", mapPinLoc.c_str(), mapId);
         }