Fail gracefully when we fail to fork the update binary

This change was original made in cw-f-dev but caused failures in
nyc-mr1-dev-plus-aosp due to lack of support for 'LOGE'

This version of the change uses the new 'LOG(ERROR)' style logging
instead.

See bug b/31395655
Test: attempt a memory intensive incremental OTA on a low-memory device

Change-Id: Ia87d989a66b0ce3f48e862abf9b9d6943f70e554

install.cpp

@@ -369,6 +369,14 @@ try_update_binary(const char* path, ZipArchive* zip, bool* wipe_cache,
     }
 
     pid_t pid = fork();
+
+    if (pid == -1) {
+        close(pipefd[0]);
+        close(pipefd[1]);
+        PLOG(ERROR) << "Failed to fork update binary";
+        return INSTALL_ERROR;
+    }
+
     if (pid == 0) {
         umask(022);
         close(pipefd[0]);