bring defaults for recrawlindex to init config

defaults/yacy.init

@@ -687,6 +687,10 @@ collection=user
 # the prereq-value is a memory pre-requisite: that much bytes must
 # be available/free in the heap; othervise the loop is not executed
 # and another idlesleep is performed
+recrawlindex_busysleep=10
+recrawlindex_idlesleep=2000
+recrawlindex_loadprereq=8.0
+recrawlindex_memprereq=1048576
 20_dhtdistribution_idlesleep=30000
 20_dhtdistribution_busysleep=15000
 20_dhtdistribution_memprereq=12582912