perf tools: Normalize sq_quote_argv() error reporting

It already returns whatever strbuf_(grow|addch)() returns in case of
failure, so just return -ENOSPC in the only case where it was die()ing.
When it returns, its only caller will call die() anyway, so no need to
be so eager, die later.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/quote.c

···
 			break;
 		ret = sq_quote_buf(dst, argv[i]);
 		if (maxlen && dst->len > maxlen)
-			die("Too many or long arguments");
+			return -ENOSPC;
 	}
 	return ret;
 }