Adding boost libraries to external lib section to make sure it lies in the end of the g++ compile command

Author: abhishekdelta

src/Makefile.am

@@ -54,6 +54,7 @@ endif
 # Set libraries external to this component.
 EXTERNAL_LIBS = -L$(thrift_home)/lib -L$(fb303_home)/lib -L$(hadoop_home)/lib -lfb303 -lthrift -lthriftnb
 EXTERNAL_LIBS += -levent -lpthread
+EXTERNAL_LIBS += $(BOOST_SYSTEM_LIB) $(BOOST_FILESYSTEM_LIB)
 if USE_SCRIBE_HDFS
   EXTERNAL_LIBS += -lhdfs -ljvm
 endif