Escape dollar sign in plugin manifest entries

Escape dollar sign in plugin manifest entries, to prevent that
it is interpreted by the shell and thus get removed.

Change-Id: Iefd8abdcd207cb985f8156c7e41c094c1aa12b27

tools/default.defs

diff --git a/tools/default.defs b/tools/default.defs
index 772862d0..76c4e87 100644
--- a/tools/default.defs
+++ b/tools/default.defs
@@ -143,6 +143,7 @@
     mf_cmd += 'echo "Implementation-Version: $v" >>$OUT;'
     mf_cmd += 'echo "Implementation-Vendor: Gerrit Code Review" >>$OUT'
     for line in manifest_entries:
+      line = line.replace('$', '\$')
       mf_cmd += ';echo "%s" >> $OUT' % line
   genrule(
     name = name + '__manifest',