dist: Update release dates for 3.1.4 to April 2019

Signed-off-by: Brian Barrett <bbarrett@amazon.com>

Author: bwbarrett

NEWS

@@ -55,7 +55,7 @@ included in the vX.Y.Z section and be denoted as:
    (** also appeared: A.B.C)  -- indicating that this item was previously
                                  included in release version vA.B.C.
 
-3.1.4 -- March, 2019
+3.1.4 -- April, 2019
 --------------------
 
 - Fix compile error when configured with --enable-mpi-java and

README

@@ -64,7 +64,7 @@ Much, much more information is also available in the Open MPI FAQ:
 ===========================================================================
 
 The following abbreviated list of release notes applies to this code
-base as of this writing (March 2019):
+base as of this writing (April 2019):
 
 General notes
 -------------