This changes the startup order a fair bit. The new order is now:

1. Do non-critical initialization that does not require a server grab
2. Take server grab
3. Create edge windows
4. Do the ICCCM check to shut down the other window manager
5. Clear error buffer
6. Attempt to take SubstructureRedirectMask
7. Clear error buffer -> if fail, exit
8. Create handles based on XQueryTree
9. Release server grab

(LP: #1085591)

[ RUN      ] CompizXorgSystemICCCM.SomeoneElseHasSubstructureRedirectMask
compiz (core) - Info: Loading plugin: core
compiz (core) - Info: Starting plugin: core
compiz (core) - Error: Another window manager is already running on screen: 0
compiz (core) - Info: Stopping plugin: core
compiz (core) - Info: Unloading plugin: core
[       OK ] CompizXorgSystemICCCM.SomeoneElseHasSubstructureRedirectMask (33 ms)
[----------] 1 test from CompizXorgSystemICCCM (34 ms total)