git-p4: Cleanup; moved the code for the initial #head or revision import into a separate function, out of P4Sync.run.

diff --git a/RelNotes b/RelNotes
index c543b1d1eedf821fe1e8c31d902a719bfc6ffb20..0de5e663a2ba03a15eb6711079c6bff0cba023cb 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.5.2.txt
\ No newline at end of file
+Documentation/RelNotes-1.5.3.txt
\ No newline at end of file