Unbreak install after repo transfers (#1523)

The directory name in the zip we download from github's release
archive will be different now that the project was renamed.
It may be renamed again in the future, so try to obtain the directory
name from the zip.

Fixes https://github.com/apache/incubator-pagespeed-ngx/issues/1521

scripts/build_ngx_pagespeed.sh

@@ -612,7 +612,9 @@ Not deleting $directory; name is suspiciously short.  Something is wrong."
     nps_downloaded="$TEMPDIR/$nps_downloaded_fname.zip"
     status "Downloading ngx_pagespeed..."
     run wget "$nps_baseurl/$tag_name.zip" -O "$nps_downloaded"
-    nps_module_dir="$BUILDDIR/$nps_downloaded_fname"
+    # Read the directory name from the zip, the first line is expected to have it.
+    nps_module_dir=$(unzip -qql "$nps_downloaded" | head -n1 | tr -s ' ' | cut -d' ' -f5-)
+    nps_module_dir="$BUILDDIR/${nps_module_dir::-1}"
     delete_if_already_exists "$nps_module_dir"
     status "Extracting ngx_pagespeed..."
     run unzip -q "$nps_downloaded" -d "$BUILDDIR"