waf: fix environment boolean values

It is more natural to use `env.FOO = True` then `env.foo = [True]`.

Tools/ardupilotwaf/boards.py

@@ -213,7 +213,7 @@ class bebop(linux):
         env.DEFINES.update(
             CONFIG_HAL_BOARD_SUBTYPE = 'HAL_BOARD_SUBTYPE_LINUX_BEBOP',
         )
-        env.STATIC_LINKING = [True]
+        env.STATIC_LINKING = True
 
 class raspilot(linux):
     def configure_env(self, env):

wscript

@@ -114,7 +114,7 @@ def configure(cfg):
     ])
 
     if cfg.options.submodule_update:
-        cfg.env.SUBMODULE_UPDATE = [True]
+        cfg.env.SUBMODULE_UPDATE = True
 
 def collect_dirs_to_recurse(bld, globs, **kw):
     dirs = []