Update ghost

Commit hash is referencing v0.5.10

library/ghost

@@ -1,6 +1,6 @@
 # maintainer: InfoSiftr <[email protected]> (@infosiftr)
 
-0.5.9: git://github.com/docker-library/ghost@4ee388e3ff8d7251cfe3f0ac062efb68a0cd2835
-0.5: git://github.com/docker-library/ghost@4ee388e3ff8d7251cfe3f0ac062efb68a0cd2835
-0: git://github.com/docker-library/ghost@4ee388e3ff8d7251cfe3f0ac062efb68a0cd2835
-latest: git://github.com/docker-library/ghost@4ee388e3ff8d7251cfe3f0ac062efb68a0cd2835
+0.5.10: git://github.com/docker-library/ghost@2b93aa26432d878a6d3b40d8cdc918a103ed2661
+0.5: git://github.com/docker-library/ghost@2b93aa26432d878a6d3b40d8cdc918a103ed2661
+0: git://github.com/docker-library/ghost@2b93aa26432d878a6d3b40d8cdc918a103ed2661
+latest: git://github.com/docker-library/ghost@2b93aa26432d878a6d3b40d8cdc918a103ed2661