BUG/MINOR: h3: add missing break on rcv_buf()

BUG/MINOR: h3: add missing break on rcv_buf()

The following patch ensures server MAX_PUSH_ID are rejected as a client.
This has been implemented by extending h3_rcv_buf().

  e4a5a64198bb084eaef2e71bfde65704a5db3931
  BUG/MINOR: h3: reject server MAX_PUSH_ID frame

Case label for MAX_PUSH_ID has been moved in the function, however the
break instruction was removed by error. Fix this by adding the missing
break statement.

This must be backported to every version the above fix is. Currently, it
is scheduled to 3.3.