releasetools: Support verity signer args.

system/extras/verity/build_verity_metadata.py now accepts
"--signer_args" to specify verity signer args.

Also remove the duplicate "--verity_signer_args" in
add_img_to_target_files.py, as we already have that in common.py.

Bug: 31500665
Test: Building and signing work w/ and w/o --signer_args.

Change-Id: I02f59c50a1ebf15c5505e9fffd5b9bbbbaa785be

tools/releasetools/add_img_to_target_files.py

@@ -41,9 +41,6 @@ Usage:  add_img_to_target_files [flag] target_files
   --is_signing
       Skip building & adding the images for "userdata" and "cache" if we
       are signing the target files.
-
-  --verity_signer_path
-      Specify the signer path to build verity metadata.
 """
 
 import sys
@@ -71,7 +68,6 @@ OPTIONS.rebuild_recovery = False
 OPTIONS.replace_verity_public_key = False
 OPTIONS.replace_verity_private_key = False
 OPTIONS.is_signing = False
-OPTIONS.verity_signer_path = None
 
 def AddSystem(output_zip, prefix="IMAGES/", recovery_img=None, boot_img=None):
   """Turn the contents of SYSTEM into a system image and store it in
@@ -452,8 +448,6 @@ def main(argv):
       OPTIONS.replace_verity_public_key = (True, a)
     elif o == "--is_signing":
       OPTIONS.is_signing = True
-    elif o == "--verity_signer_path":
-      OPTIONS.verity_signer_path = a
     else:
       return False
     return True
@@ -463,8 +457,7 @@ def main(argv):
       extra_long_opts=["add_missing", "rebuild_recovery",
                        "replace_verity_public_key=",
                        "replace_verity_private_key=",
-                       "is_signing",
-                       "verity_signer_path="],
+                       "is_signing"],
       extra_option_handler=option_handler)