Merge pull request #3210 from jsquyres/pr/v2.1.0/update-to-v2.1.0rc4

VERSION: Bump to 2.1.0rc4

Author: jsquyres

VERSION

@@ -24,7 +24,7 @@ release=0
 # requirement is that it must be entirely printable ASCII characters
 # and have no white space.
 
-greek=rc3
+greek=rc4
 
 # If repo_rev is empty, then the repository version number will be
 # obtained during "make dist" via the "git describe --tags --always"