Workaround for SVNKIT-430. There were two issues fixed as part of this commit:
1. Working copy for 1.7 was being stored as 100. Instead we deprecated the 100 value, and switch to using ISVNWCDb.WC_FORMAT_17. The changes in the global.jelly file are there for maintaining backwards compatibility when upgrading to a new version, but maintaining the 1.7 workspace.
2. Actual workaround for SVNKIT-430. Previous versions used the doCheckout method, however because of SVNKIT-430 the workspace format would default to 1.8. Instead we get the checkout object and add the working copy format manually.
Fixed test unit. Add ignore externals to checkout call.