vendor: upgrade go-mysql-server and go-git

Gopkg.toml

@@ -1,6 +1,6 @@
 [[constraint]]
   name = "gopkg.in/src-d/go-mysql-server.v0"
-  revision = "5a9075414ef5cc7799a551289f81cd6d34242eaf"
+  revision = "31ad0f968a8823de219f1db70e2b4890f06ff48b"
 
 [[constraint]]
   name = "github.com/jessevdk/go-flags"
@@ -17,7 +17,7 @@
 [[constraint]]
   name = "gopkg.in/src-d/go-git.v4"
   source = "github.com/src-d/go-git"
-  version = "4.8.1"
+  version = "4.9.1"
 
 [[constraint]]
   name = "gopkg.in/src-d/go-git-fixtures.v3"

docs/using-gitbase/functions.md

@@ -95,4 +95,4 @@ Also, if you want to retrieve values from a non common property, you can pass it
 
 ## Standard functions
 
-You can check standard functions in [`go-mysql-server` documentation](https://github.com/src-d/go-mysql-server/tree/5a9075414ef5cc7799a551289f81cd6d34242eaf#custom-functions).
+You can check standard functions in [`go-mysql-server` documentation](https://github.com/src-d/go-mysql-server/tree/31ad0f968a8823de219f1db70e2b4890f06ff48b#custom-functions).

docs/using-gitbase/indexes.md

@@ -26,4 +26,4 @@ and for the second query also two indexes will be used and the result will be a
 
 You can find some more examples in the [examples](./examples.md#create-an-index-for-columns-on-a-table) section.
 
-See [go-mysql-server](https://github.com/src-d/go-mysql-server/tree/5a9075414ef5cc7799a551289f81cd6d34242eaf#indexes) documentation for more details
+See [go-mysql-server](https://github.com/src-d/go-mysql-server/tree/31ad0f968a8823de219f1db70e2b4890f06ff48b#indexes) documentation for more details

docs/using-gitbase/supported-clients.md

@@ -1,3 +1,3 @@
 ## Supported clients
 
-To see the supported MySQL clients and examples about how to use them, take a look [here](https://github.com/src-d/go-mysql-server/blob/5a9075414ef5cc7799a551289f81cd6d34242eaf/SUPPORTED_CLIENTS.md).
+To see the supported MySQL clients and examples about how to use them, take a look [here](https://github.com/src-d/go-mysql-server/blob/31ad0f968a8823de219f1db70e2b4890f06ff48b/SUPPORTED_CLIENTS.md).

docs/using-gitbase/supported-syntax.md

@@ -1,3 +1,3 @@
 ## Supported syntax
 
-To see the SQL subset currently supported take a look at [this list](https://github.com/src-d/go-mysql-server/blob/5a9075414ef5cc7799a551289f81cd6d34242eaf/SUPPORTED.md) from [src-d/go-mysql-server](https://github.com/src-d/go-mysql-server).
+To see the SQL subset currently supported take a look at [this list](https://github.com/src-d/go-mysql-server/blob/31ad0f968a8823de219f1db70e2b4890f06ff48b/SUPPORTED.md) from [src-d/go-mysql-server](https://github.com/src-d/go-mysql-server).