Reinstate assert() statements in os_unix.c that were removed to allow

wal-mode SHARED locks to be taken over more than one locking slot
(this branch no longer does that, so the assert() statements can go
back in).

FossilOrigin-Name: fcb7348ba190e48112a681f704313a733f7a377456e7c1d6845ba34c270d86b6

diff --cc manifest
index 661d3c7b8aae8be80ce4e301d6aa1e886855b150,575be8a9db4b0e0612d32dbd64f80fff8b863caf..905acc096acdd84044144100903cb2ac6f5f3594
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Merge\slatest\swal2\schanges\sinto\sthis\sbranch.
- D 2019-01-02T16:30:10.490
 -C Reinstate\sassert()\sstatements\sin\sos_unix.c\sthat\swere\sremoved\sto\sallow\swal-mode\nSHARED\slocks\sto\sbe\staken\sover\smore\sthan\sone\slocking\sslot\s(this\sbranch\sno\nlonger\sdoes\sthat,\sso\sthe\sassert()\sstatements\scan\sgo\sback\sin).
 -D 2019-01-02T17:00:00.197
++C Reinstate\sassert()\sstatements\sin\sos_unix.c\sthat\swere\sremoved\sto\sallow\nwal-mode\sSHARED\slocks\sto\sbe\staken\sover\smore\sthan\sone\slocking\sslot\n(this\sbranch\sno\slonger\sdoes\sthat,\sso\sthe\sassert()\sstatements\scan\sgo\nback\sin).
++D 2019-01-02T17:08:06.138
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in d8b254f8bb81bab43c340d70d17dc3babab40fcc8a348c8255881f780a45fee6
@@@ -499,12 -495,12 +499,12 @@@ F src/os.c 8aeb0b0f40f8f5b0da03fe497066
  F src/os.h 48388821692e87da174ea198bf96b1b2d9d83be5dfc908f673ee21fafbe0d432
  F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
  F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
- F src/os_unix.c 1aa113b261a0ad44fd410a001f6e39bfc1ebd4279b2fb8c2d636a7620d76a45a
 -F src/os_unix.c f6e91b8fd82af7afbfd073c4974ad6cdb8e62d9f65ceddb45167835a0567fdc0
++F src/os_unix.c 86eca42c3d955bebea0082450f978e5633448235f03f86b27a02538bb26e7fff
  F src/os_win.c 85d9e532d0444ab6c16d7431490c2e279e282aa0917b0e988996b1ae0de5c5a0
  F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 -F src/pager.c dc6d0acb3f89b4dcb801c86a0e722c1bde116e058c7216ff74341812a38bbdd9
 -F src/pager.h 3abf6d65199fd0680b26a047c6167a96a4d6ead7535e02522b79f0fb27a3edec
 -F src/parse.y a3c0db595bc642c6ee1d72869842f7f5b0b6ebeb91c21d0a7cba631d27e7afbd
 +F src/pager.c 24dbb25d447629bc8167dcf16dcb449a6eb2067393935d97ff42377798e44979
 +F src/pager.h d8cf37b3415c742d1f267ae2e0e6495826a72d403cbdbefdab2e2f5ff2a1dde7
 +F src/parse.y 8206217fe7fa96652aa1b8a797246e23b30a9d4c1a5175d9c12b13750f51dc2f
  F src/pcache.c 696a01f1a6370c1b50a09c15972bc3bee3333f8fcd1f2da8e9a76b1b062c59ee
  F src/pcache.h 4f87acd914cef5016fae3030343540d75f5b85a1877eed1a2a19b9f284248586
  F src/pcache1.c ddc9fc7d9861cf3a1f30660264b76b1ae9e1dce5dbba085cf001d5cb6b41cf8c
@@@ -1823,7 -1806,7 +1823,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 1625887c0240eb1cb37e41d79e789c4ff311352c5708e6a2d3ed1b223ff382e3 87ef68f9174b5e21fa2fb4f2fa23e0ecd6a0ea854422c8aa74cd7306a1ed8427
- R 4dfccbc013208e67a5138d4fe488e5bf
 -P 87ef68f9174b5e21fa2fb4f2fa23e0ecd6a0ea854422c8aa74cd7306a1ed8427
 -R 81c151bc78b917b5a505ba7d0041b59f
++P c31eeb3c87f260fa192638b3610a4d3b84b2c26cfaefc97ed63910495403f8c9 8445fb6d5dae98a0129514a10a15f08412bac5a1d8114b12e592c744ea2bc4c9
++R 0806996acba6e0b3331e631071ee176c
  U dan
- Z 8d740846efc79a7e725157c7768bb258
 -Z 69b1e094c88bc1f9442e8f44aee16f43
++Z 44e579b069341a68865674e64e97136d

diff --cc manifest.uuid
index ad2820df3374a48b92a0ab6b04713c082dd76b81,56ed701164d0fd9505982bbffde3fa010db74dbb..b187037ed0abf08983f3f9d1d008f9cfe6314b8c
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- c31eeb3c87f260fa192638b3610a4d3b84b2c26cfaefc97ed63910495403f8c9
 -8445fb6d5dae98a0129514a10a15f08412bac5a1d8114b12e592c744ea2bc4c9
++fcb7348ba190e48112a681f704313a733f7a377456e7c1d6845ba34c270d86b6

diff --cc src/os_unix.c
Simple merge