Fix a few cppcheck issues

Found the following:

* Potential stack explosions with alloca() usage on potentially large
strings
* Memory leaks in WriteEngineServer
* Stack usage out of scope in dataconvert
* A typo in an 'if' statement in dataconvert

writeengine/bulk/we_colbuf.cpp

@@ -133,7 +133,7 @@ int ColumnBuffer::writeToFile(int startOffset, int writeSize, bool fillUpWEmptie
 
     if (nitems != 1)
     {
-        delete newBuf;
+        delete [] newBuf;
         return ERR_FILE_WRITE;
     }
 
@@ -141,7 +141,7 @@ int ColumnBuffer::writeToFile(int startOffset, int writeSize, bool fillUpWEmptie
     Stats::stopParseEvent(WE_STATS_WRITE_COL);
 #endif
 
-    delete newBuf;
+    delete [] newBuf;
     return NO_ERROR;
 }
 

writeengine/bulk/we_columninfocompressed.cpp

@@ -411,6 +411,7 @@ int ColumnInfoCompressed::truncateDctnryStore(
             fLog->logMsg( oss.str(), rc, MSGLVL_ERROR );
             fTruncateDctnryFileOp.closeFile( dFile );
 
+            delete [] pointerHdr;
             return rc;
         }