Avoid unnecessary cursor seeking when performing an UPSERT.

FossilOrigin-Name: 693a3dcbdd8fb2d516c0f46fdbb478838cde675afc1026740e942705aac3c07f

diff --cc manifest
index 8aa4cda223296881cd1d554acb754577a175ca15,c98c1abd7004ab3be4a02967ddac838d5def5120..304c8968c55a319b70e0753cf9344071ce04388c
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\stest\scases\sfor\sUPSERT.\sAnd\sa\sfix\sfor\sa\s"REPLACE\sINTO\s...\sON\sCONFLICT"\nstatement\swhere\sthe\snew\srow\sconflicts\swith\sboth\sthe\sIPK\sand\sthe\sON\sCONFLICT\nindexes.
- D 2018-04-20T15:34:08.067
 -C Improved\sVDBE\scomment\son\sUPSERT\scode.
 -D 2018-04-20T16:49:51.077
++C Avoid\sunnecessary\scursor\sseeking\swhen\sperforming\san\sUPSERT.
++D 2018-04-20T17:02:16.531
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in 5ce9343cba9c189046f1afe6d2bcc1f68079439febc05267b98aec6ecc752439
@@@ -1724,7 -1724,7 +1724,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P c37f39d18d41ae5ba6c4561d87cbbf71f3b6896b86cc5cff9cdf046b02dc521a
- R ae514c5e5a987302d42c4363153aaf33
- U dan
- Z a0358cccdac92456839b19732d4467cc
 -P d1906689abdb685f78aa97bca4bf301204d12846016d27bc86dcc9ce2b024d24
++P d8eb9f8d9b61400c7e12f01ef5c233257b03532221f7c7a8386f7ac2db439626 131ed95e1452a5b0d92341c48a5d3915b328ccfce2cf605f702428ae7ee3e21b
+ R 18734526551b7a3f2bbebfc4bb6f5573
++T +closed 131ed95e1452a5b0d92341c48a5d3915b328ccfce2cf605f702428ae7ee3e21b
+ U drh
 -Z 95143f322f298a42bef8b7fc14836f21
++Z 23a2cba3b6d85936a323e52ae5cb1690

diff --cc manifest.uuid
index 67904869cc1bb1cf62cea864147a517af3b53af9,e5eb6bed9a161f8004d042e50854fc529ba80787..15ad2f67a9c54098a4b517db85f7808630a8a801
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- d8eb9f8d9b61400c7e12f01ef5c233257b03532221f7c7a8386f7ac2db439626
 -131ed95e1452a5b0d92341c48a5d3915b328ccfce2cf605f702428ae7ee3e21b
++693a3dcbdd8fb2d516c0f46fdbb478838cde675afc1026740e942705aac3c07f