Prepare for WORK_MORE_C

Add the new enum value and case statements as appropriate.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2279)

ssl/statem/statem.c

@@ -564,6 +564,7 @@ static SUB_STATE_RETURN read_state_machine(SSL *s)
             case WORK_ERROR:
             case WORK_MORE_A:
             case WORK_MORE_B:
+            case WORK_MORE_C:
                 return SUB_STATE_ERROR;
 
             case WORK_FINISHED_CONTINUE:
@@ -706,6 +707,7 @@ static SUB_STATE_RETURN write_state_machine(SSL *s)
             case WORK_ERROR:
             case WORK_MORE_A:
             case WORK_MORE_B:
+            case WORK_MORE_C:
                 return SUB_STATE_ERROR;
 
             case WORK_FINISHED_CONTINUE:
@@ -745,6 +747,7 @@ static SUB_STATE_RETURN write_state_machine(SSL *s)
             case WORK_ERROR:
             case WORK_MORE_A:
             case WORK_MORE_B:
+            case WORK_MORE_C:
                 return SUB_STATE_ERROR;
 
             case WORK_FINISHED_CONTINUE:

ssl/statem/statem.h

@@ -27,7 +27,9 @@ typedef enum {
     /* We're working on phase A */
     WORK_MORE_A,
     /* We're working on phase B */
-    WORK_MORE_B
+    WORK_MORE_B,
+    /* We're working on phase C */
+    WORK_MORE_C
 } WORK_STATE;
 
 /* Write transition return codes */