[seahorse] README: remove _ prefix from build dir.

[Niels De Graef <nielsdg src gnome org>]

commit b6f9b80dd301050e58b3cab6bc218731a107b3d6
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Mon Nov 27 18:43:06 2017 +0100

    README: remove _ prefix from build dir.
    
    Since we're no longer using a directory with the name `build` anymore,
    it's safe to use it as the name for the build directory. (It's also
    easier to type)

 README.md |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/README.md b/README.md
index 7d8726b..85140fd 100644
--- a/README.md
+++ b/README.md
@@ -11,9 +11,9 @@ nautilus or gedit.
 ## Building
 You can build and install Seahorse using [Meson](http://mesonbuild.com/):
 ```sh
-meson _build
-ninja -C _build
-ninja -C _build install
+meson build
+ninja -C build
+ninja -C build install
 ```
 
 ## Issue tracker