Mesa (18.1): Bump version to rc4

[Dylan Baker]

Module: Mesa
Branch: 18.1
Commit: 630559e05443b1df6fedb7576c2291af99c3dec5
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=630559e05443b1df6fedb7576c2291af99c3dec5

Author: Dylan Baker <dylan at pnwbakers.com>
Date:   Fri May 11 08:34:16 2018 -0700

Bump version to rc4

---

 VERSION | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/VERSION b/VERSION
index 5b3a4a1f0b..628d7e49e3 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-18.1.0-rc3
+18.1.0-rc4