update the latest version in README.fb to 2.7

Kai Liu · Kai Liu · commit fe030bd1ca77 · 2013-12-30T16:16:24.000-08:00
diff --git a/README.fb b/README.fb
@@ -1,3 +1,3 @@
 * Detailed instructions on how to compile using fbcode and jemalloc
 
-* Latest release is 2.6.fb
+* Latest release is 2.7.fb

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,3 @@`
`1`	`1`	`* Detailed instructions on how to compile using fbcode and jemalloc`
`2`	`2`
`3`		`-* Latest release is 2.6.fb`
	`3`	`+* Latest release is 2.7.fb`