Fix for CA link disconnect detection

dbCa's doLocked() method must run the callback even when the link
is disconnected to allow alarms to be triggered by softDev support.

Patch from Sebastian Marsching
Also removes testToDo from rec/test/regressTest.c

Fixes lp: #1798855

src/ioc/db/dbCa.c

@@ -703,7 +703,12 @@ static long doLocked(struct link *plink, dbLinkUserCallback rtn, void *priv)
     caLink *pca;
     long status;
 
-    pcaGetCheck
+    assert(plink);
+    if (plink->type != CA_LINK) return -1;
+    pca = (caLink *)plink->value.pv_link.pvt;
+    assert(pca);
+    epicsMutexMustLock(pca->lock);
+    assert(pca->plink);
     status = rtn(plink, priv);
     epicsMutexUnlock(pca->lock);
     return status;

src/std/rec/test/regressTest.c

@@ -133,10 +133,8 @@ void testCADisconn(void)
     startRegressTestIoc("badCaLink.db");
 
     testdbPutFieldOk("ai:disconn.PROC", DBF_LONG, 1);
-    testTodoBegin("lp:1798855");
     testdbGetFieldEqual("ai:disconn.SEVR", DBF_LONG, INVALID_ALARM);
     testdbGetFieldEqual("ai:disconn.STAT", DBF_LONG, LINK_ALARM);
-    testTodoEnd();
 }