Description of problem:
At hsm.py there is a for loop that go over each iscsi session.
In the loop there is a full iscsi scan : iscsiadm -m session -R
Since it is a full scan (no SID attached to the command) it scans all the sessions thus need to remove the for loop to avoid additional scans that are not needed.

Version-Release number of selected component (if applicable):
VDSM 4.19.17

How reproducible:
Always

Steps to Reproduce:
1.execute connectStorageServer on a system with 4 iscsi targets
2.see that full iscsi scans is executed 4 times

Actual results:
4 full iscsi scans is executed 

Expected results:
Only one full iscsi scan is executed in connectStorageServer


Additional info:
The code section -

        for conDef in conList:
            conInfo = _connectionDict2ConnectionInfo(domType, conDef)
            conObj = storageServer.ConnectionFactory.createConnection(conInfo)
            try:
                self._connectStorageOverIser(conDef, conObj, domType)
                conObj.connect()
            except Exception as err:
                self.log.error(
                    "Could not connect to storageServer", exc_info=True)
                status, _ = self._translateConnectionError(err)
            else:
                status = 0
                # In case there were changes in devices size
                # while the VDSM was not connected, we need to
                # call refreshStorage.
                if domType in (sd.FCP_DOMAIN, sd.ISCSI_DOMAIN):
                    sdCache.refreshStorage()