Changed exception message method name

Changed method name from setMissingExceptionMessage to
reportMissingExceptionWithMessage to be more consistent with the
existing API.

src/main/java/org/junit/rules/ExpectedException.java

@@ -118,7 +118,7 @@ public ExpectedException handleAssumptionViolatedExceptions() {
      * @param providedMessage exception detail message
      * @return self
      */
-    public ExpectedException setMissingExceptionMessage(String providedMessage) {
+    public ExpectedException reportMissingExceptionWithMessage(String providedMessage) {
     	missingExceptionMessage = providedMessage;
     	return this;
     }

src/test/java/org/junit/tests/experimental/rules/ExpectedExceptionTest.java

@@ -378,7 +378,7 @@ public static class CustomMessageWithoutExpectedException {
         @Test
         public void noThrow() {
             thrown.expect(IllegalArgumentException.class);
-            thrown.setMissingExceptionMessage(ARBITRARY_MESSAGE);
+            thrown.reportMissingExceptionWithMessage(ARBITRARY_MESSAGE);
         }
     }
 }