syncd: Fix profile iterator bug (#789)

As I didn't see SAI specifying that the user of the service table should reset the iterator before iterating over the values, I think this would come as a surprise to most vendors implementing SAI. Because the iterator was first stored before adding any values to the map, it would be pointing to the profile's .end(), thus if a SAI implementation would try iterating over the values, it'd get none until it'd reset the iterator.

syncd/Syncd.cpp

@@ -95,10 +95,10 @@ Syncd::Syncd(
 
     m_manager = std::make_shared<FlexCounterManager>(m_vendorSai, m_contextConfig->m_dbCounters);
 
-    m_profileIter = m_profileMap.begin();
-
     loadProfileMap();
 
+    m_profileIter = m_profileMap.begin();
+
     // we need STATE_DB ASIC_DB and COUNTERS_DB
 
     m_dbAsic = std::make_shared<swss::DBConnector>(m_contextConfig->m_dbAsic, 0);