Modify redis.conf to work with Redis > 2.4

Virtual Memory is deprecated now and throws an error at startup. To
handle it, the vm-swap-file option was removed.

Reference:  http://redis.io/topics/virtual-memory
Tested and worked with: Redis server v=2.6.9 sha=00000000:0 malloc=libc
bits=64

dev/redis/redis.conf

@@ -14,5 +14,3 @@ save 60 10000
 dbfilename dump.rdb
 dir dev/redis/
 requirepass i-am-using-redis-in-development-mode-for-npm-www
-
-vm-swap-file dev/redis/redis.swap