patch 8.0.1155: Ruby command triggers a warning

Problem:    Ruby command triggers a warning when RUBYOPT is set to "-w".
Solution:   use "-e_=0" instead of "-e0". (Masataka Pocke Kuwabara, closes
            #2143)
diff --git a/src/if_ruby.c b/src/if_ruby.c
index c1b42e6..f3434a9 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -882,7 +882,7 @@
 #ifdef RUBY19_OR_LATER
 	    {
 		int dummy_argc = 2;
-		char *dummy_argv[] = {"vim-ruby", "-e0"};
+		char *dummy_argv[] = {"vim-ruby", "-e_=0"};
 		ruby_options(dummy_argc, dummy_argv);
 	    }
 	    ruby_script("vim-ruby");