DO NOT MERGE Fail gracefully when we fail to fork the update binary

See bug b/31395655

Change-Id: Ic5a046bc80ea88d7eb52755838bdbf4e1e47da50

install.cpp

@@ -374,6 +374,14 @@ try_update_binary(const char* path, ZipArchive* zip, bool* wipe_cache,
     }
 
     pid_t pid = fork();
+
+    if (pid == -1) {
+        close(pipefd[0]);
+        close(pipefd[1]);
+        LOGE("Failed to fork update binary: %s\n", strerror(errno));
+        return INSTALL_ERROR;
+    }
+
     if (pid == 0) {
         umask(022);
         close(pipefd[0]);