unbundle: remove obsolete GYP script

build/linux/unbundle/README

Index: build/linux/unbundle/README
diff --git a/build/linux/unbundle/README b/build/linux/unbundle/README
index 8c77b75b66efbe522646c8b870e1907f4fec580a..47336a1a330caa1ff6786eabb56df61a736425f7 100644
--- a/build/linux/unbundle/README
+++ b/build/linux/unbundle/README
@@ -37,19 +37,6 @@ Usage:
    NOTE: by default this will not remove anything (for safety). Pass
    --do-remove flag to actually remove files.
 
-2. Pick the script to run depending on whether you use GYP or GN:
+2. replace_gn_files.py --system-libraries lib...
 
-2a. replace_gyp_files.py <gyp-flags>
-
-    For example: replace_gyp_files.py -Duse_system_harfbuzz=1
-
-    The script ignores flags other than -D for convenience. This makes it
-    possible to have a variable e.g. ${myconf} with all the options, and
-    execute:
-
-    build/linux/unbundle/replace_gyp_files.py ${myconf}
-    build/gyp_chromium ${myconf}
-
-2b. replace_gn_files.py --system-libraries lib...
-
-    For example: replace_gn_files.py --system-libraries libxml
+   For example: replace_gn_files.py --system-libraries libxml