Fix #64, add CFE_SB_InitMsg() for housekeeping UT (HOTFIX)

The FSW code relies on the message being pre-initalized which
needs to be done explicitly in unit test code.

unit-test/coveragetest/coveragetest_sample_app.c

@@ -375,6 +375,18 @@ void Test_SAMPLE_ReportHousekeeping(void)
  SAMPLE_AppData.CmdCounter = 22;
  SAMPLE_AppData.ErrCounter = 11;
 
+ /*
+ * CFE_SB_InitMsg() needs to be done to set the emulated MsgId and Length.
+ *
+ * The FSW code only does this once during init and relies on it
+ * remaining during the SAMPLE_ReportHousekeeping(). This does
+ * not happen during UT so it must be initialized again here.
+ */
+ CFE_SB_InitMsg(&SAMPLE_AppData.HkBuf.MsgHdr,
+ SAMPLE_APP_HK_TLM_MID,
+ sizeof(SAMPLE_AppData.HkBuf),
+ true);
+
  /*
  * Set up to "capture" the telemetry message
  */