dirmods: Update to take absolute paths

Dirmods currently expects a path relative to the top of the build. If
an abs path is passed, it will never match anything.

Modify so that if path is absolute, we fix-up the path relative to
ANDROID_BUILD_TOP.

Test: manual
Bug: trivial
Change-Id: Iad99228078dc693ab5f7957e007fe1bd5cea07d2

bin/dirmods

@@ -35,6 +35,14 @@ def main():
     args = parser.parse_args()
 
     d = os.path.normpath(args.path)
+    # Fix absolute path to be relative to build top
+    if os.path.isabs(d):
+        base = os.environ.get('ANDROID_BUILD_TOP')
+        if base:
+            base = os.path.normpath(base) + os.path.sep
+            if d.startswith(base):
+                d = d[len(base):]
+
     prefix = d + '/'
 
     module_info = modinfo.ReadModuleInfo()