build: update waf to version 2.0.6

Cleanup in most build scripts

Change-Id: Ib024e95fb6f80e72b0c00e1dc8bb9300d6c5f191
diff --git a/.waf-tools/coverage.py b/.waf-tools/coverage.py
index ce92883..cc58165 100644
--- a/.waf-tools/coverage.py
+++ b/.waf-tools/coverage.py
@@ -1,15 +1,15 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 
-from waflib import TaskGen, Logs
+from waflib import TaskGen
 
 def options(opt):
-    opt.add_option('--with-coverage', action='store_true', default=False, dest='with_coverage',
-                   help='''Set compiler flags for gcc to enable code coverage information''')
+    opt.add_option('--with-coverage', action='store_true', default=False,
+                   help='Add compiler flags to enable code coverage information')
 
 def configure(conf):
     if conf.options.with_coverage:
         if not conf.options.debug:
-            conf.fatal("Code coverage flags require debug mode compilation (add --debug)")
+            conf.fatal('Code coverage flags require debug mode compilation (add --debug)')
         conf.check_cxx(cxxflags=['-fprofile-arcs', '-ftest-coverage', '-fPIC'],
                        linkflags=['-fprofile-arcs'], uselib_store='GCOV', mandatory=True)