Documentation/Builds: Delete previously generated docs

As the Makefile is no longer responsible for calling the extension and
instrumentation documentation ensure any previously generated
documentation is deleted from the respective build file.

doc/build_extension_docs.py

@@ -17,6 +17,7 @@
 
 import os
 import sys
+import shutil
 
 from wlauto import ExtensionLoader
 from wlauto.utils.doc import get_rst_from_extension, underline
@@ -30,6 +31,9 @@ def generate_extension_documentation(source_dir, outdir, ignore_paths):
     loader = ExtensionLoader(keep_going=True)
     loader.clear()
     loader.update(paths=[source_dir], ignore_paths=ignore_paths)
+    if os.path.exists(outdir):
+        shutil.rmtree(outdir)
+    os.makedirs(outdir)
     for ext_type in loader.extension_kinds:
         if not ext_type in GENERATE_FOR:
             continue

doc/build_instrumentation_method_map.py

@@ -38,6 +38,8 @@ def generate_instrumentation_method_map(outfile):
                                        headers=['method name', 'signal'], align='<<')
     priority_table = format_simple_table([(escape_trailing_underscore(k), v)  for k, v in PRIORITY_MAP.iteritems()],
                                          headers=['prefix', 'priority'],  align='<>')
+    if os.path.isfile(outfile):
+        os.unlink(outfile)
     with open(OUTPUT_TEMPLATE_FILE) as fh:
         template = string.Template(fh.read())
     with open(outfile, 'w') as wfh: