ut_sb_stubs.c decription comment for CFE_SB_RcvMsg does not match code

[asgibson]

Describe the bug
In ut_sb_stubs.c description comment for CFE_SB_RcvMsg incorrectly states that first call returns CFE_SUCCESS, while additional calls return -1. It appears that it will always return CFE_SUCCESS.

To Reproduce
Steps to reproduce the behavior:

1. Write a test where CFE_SB_RcvMsg is called at least twice.
2. Check result on first call == CFE_SUCCESS, will pass
3. Check result on second call == -1, will fail (result is CFE_SUCCESS instead)
4. additional calls have same result as 3 above.

Expected behavior
Rewrite comment to show that result returned is always CFE_SUCCESS, unless the commented behavior is what is desired, then fix code to accomplish that.

Code snips

/*****************************************************************************/
/**
** \brief CFE_SB_RcvMsg stub function
**
** \par Description
**        This function is used to mimic the response of the cFE SB function
**        CFE_SB_RcvMsg.  By default it will return the TIMEOUT error response,
**        unless the test setup sequence has indicated otherwise.
**
** \par Assumptions, External Events, and Notes:
**        None
**
** \returns
**        Returns CFE_SUCCESS on the first call, then -1 on the second.
**
******************************************************************************/
int32 CFE_SB_RcvMsg(CFE_SB_MsgPtr_t *BufPtr,
                    CFE_SB_PipeId_t PipeId,
                    int32 TimeOut)
{
    int32 status;
    static union
    {
        CFE_SB_Msg_t Msg;
        uint8 Ext[CFE_MISSION_SB_MAX_SB_MSG_SIZE];
    } Buffer;

    status = UT_DEFAULT_IMPL(CFE_SB_RcvMsg);

    if (status >= 0)
    {
        if (UT_Stub_CopyToLocal(UT_KEY(CFE_SB_RcvMsg), (uint8*)BufPtr, sizeof(*BufPtr)) < sizeof(*BufPtr))
        {
            memset(&Buffer, 0, sizeof(Buffer));
            *BufPtr = &Buffer.Msg;
        }
    }

    return status;
}

System observed on:

• Hardware: PC
• OS: RHEL Workstation 7.6 (Maipo), Linux 3.10.0-1062.1.2.el7.x86_64
• Versions cFE 6.7

Additional context
Add any other context about the problem here.

Reporter Info
Alan Gibson, NASA, GSFC-0587

[skliper]

This function was deprecated in #1015, closing issue.