git-p4: move to toplevel

Move git-p4 out of contrib/fast-import into the main code base,
aside other foreign SCM tools.

Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/.gitignore b/.gitignore
index 87fcc5f..5a0782f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -92,6 +92,7 @@
 /git-name-rev
 /git-mv
 /git-notes
+/git-p4
 /git-pack-redundant
 /git-pack-objects
 /git-pack-refs