Warn loudly and do not set bpf.progs_loaded property on critical bpf load failure.

Reasoning: critical load failures for netd bpf programs will just result
in unpredictable behaviour later on.  For example netd/systemserver
crash loops.

Test: builds
Bug: 150040815
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Iefa01e60cd0a9a223e96411726a199bfb4857a5a
diff --git a/libbpf_android/include/libbpf_android.h b/libbpf_android/include/libbpf_android.h
index 0a01c85..3810d07 100644
--- a/libbpf_android/include/libbpf_android.h
+++ b/libbpf_android/include/libbpf_android.h
@@ -25,7 +25,7 @@
 namespace bpf {
 
 // BPF loader implementation. Loads an eBPF ELF object
-int loadProg(const char* elfpath);
+int loadProg(const char* elfPath, bool* isCritical);
 
 // Wait for bpfloader to load BPF programs.
 void waitForProgsLoaded();