Resolution:
It is possible to change number of log files generated by the adapter in the following way:-

1)    Open the project in designer and create a global variable with name “LogFileCount”.
2)    Then go to fileSink configuration panel which comes under RemedyAdapterConfiguration/Advanced/
Log Sinks in designer.
3) Set the File Count with the value in Global Variable “LogFileCount".
4)    After this open the adapter .tra file and create a new entry under Global Variable section
               "tibco.clientVar.&ltGlobal Variable Name>=&ltModified Value>”
5) Save the .tra file.