NetBpfLoad: 4.14+ fail hard on bpfGetFdProgId() failure

This should always work on 4.14+

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I50fc17ff5b77f279cb741d6ef72e0519733ec881
diff --git a/bpf/loader/NetBpfLoad.cpp b/bpf/loader/NetBpfLoad.cpp
index c67be66..36dce54 100644
--- a/bpf/loader/NetBpfLoad.cpp
+++ b/bpf/loader/NetBpfLoad.cpp
@@ -1102,10 +1102,13 @@
             }
         }
 
-        int progId = bpfGetFdProgId(fd);
-        if (progId == -1) {
-            ALOGE("bpfGetFdProgId failed, ret: %d [%d]", progId, errno);
-        } else {
+        if (isAtLeastKernelVersion(4, 14, 0)) {
+            int progId = bpfGetFdProgId(fd);
+            if (progId == -1) {
+                const int err = errno;
+                ALOGE("bpfGetFdProgId failed, errno: %d", err);
+                return -err;
+            }
             ALOGI("prog %s id %d", progPinLoc.c_str(), progId);
         }
     }