Update _clang_format to avoid adding a space in list-initialization

The current style specification for clang-format will add a space
between an identifier and an initializer_list in list-initialization.

For example:

```
auto foo{bar};
```

Would be modified to:

```
auto foo {bar};
```

The Qt Style Guidelines (https://wiki.qt.io/Qt_Coding_Style) do not seem
to dictate anything about this case, while dictating about a general
use of scope-delimiting braces that, arguably, does not apply here.

Following a rationale that is similar to the one in Google's C++ Style
Guide (https://google.github.io/styleguide/cppguide.html#Braced_Initializer_List_Format),
"SpaceBeforeCpp11BracedList" is now set to false to avoid the addition
of the aforementioned space.

Change-Id: Ic499994a24293a634858889352c717248b8d11e3
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

_clang-format

@@ -83,3 +83,8 @@ ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH, forever, Q_FOREVER, QBENCH
 
 # Break constructor initializers before the colon and after the commas.
 BreakConstructorInitializers: BeforeColon
+
+# Avoids the addition of a space between an identifier and the
+# initializer list in list-initialization.
+SpaceBeforeCpp11BracedList: false
+