[release] Prepare to release AutoValue 1.4-rc1

Author: cgruber

value/pom.xml

@@ -26,7 +26,7 @@
 
   <groupId>com.google.auto.value</groupId>
   <artifactId>auto-value</artifactId>
-  <version>1.4-SNAPSHOT</version>
+  <version>1.4-rc1</version>
   <name>AutoValue</name>
   <description>
     Immutable value-type code generation for Java 1.6+.