Fix a harmless use of an uninitialized variable following system errors

in the multi-threaded sorter.

FossilOrigin-Name: 4bb2c1df105c2d21f5c4c7ef656ff1d6e15f78bc

manifest

@@ -1,5 +1,5 @@
-C Remove\san\sunused\sfield\sfrom\sthe\sMemPage\sobject.
-D 2016-01-12T04:08:54.028
+C Fix\sa\sharmless\suse\sof\san\suninitialized\svariable\sfollowing\ssystem\serrors\nin\sthe\smulti-threaded\ssorter.
+D 2016-01-12T14:10:05.866
 F Makefile.in 7c8cc4c2f0179efc6fa9492141d1fb65f4807054
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc e45d8b9b56dfa3f2cd860b2c28bd9d304513b042
@@ -405,7 +405,7 @@ F src/vdbeapi.c 020681b943e77766b32ae1cddf86d7831b7374ca
 F src/vdbeaux.c f2e6b4fae037db04323be8de7bcd266375746471
 F src/vdbeblob.c fdc4a81605ae7a35ae94a55bd768b66d6be16f15
 F src/vdbemem.c fdd1578e47bea61390d472de53c565781d81e045
-F src/vdbesort.c a7ec02da4494c59dfd071126dd3726be5a11459d
+F src/vdbesort.c 0971557e5d3c289e46f56a52aed2197c13251de7
 F src/vdbetrace.c 8befe829faff6d9e6f6e4dee5a7d3f85cc85f1a0
 F src/vtab.c 2a8b44aa372c33f6154208e7a7f6c44254549806
 F src/vxworks.h 974e7d9a98f602d6310d563e1dc4e08f9fc48e47
@@ -1407,7 +1407,7 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 1f44a9bdc1577aed088d9b91882527228015dcd3
-R dcacd681598087d316aa7da66fd3e6ff
+P 5fc0a4c1f353c4c06fcbc4bce8bbe1897ef49eee
+R 92b34da2a8b41bb1db044333a3c02410
 U drh
-Z a106a14306903405633952b5120c8bc2
+Z e6a278c031968913cb3469aed14f2f8a

manifest.uuid

@@ -1 +1 @@
-5fc0a4c1f353c4c06fcbc4bce8bbe1897ef49eee
+4bb2c1df105c2d21f5c4c7ef656ff1d6e15f78bc

src/vdbesort.c

@@ -737,7 +737,7 @@ static int vdbePmaReaderInit(
 
   rc = vdbePmaReaderSeek(pTask, pReadr, pFile, iStart);
   if( rc==SQLITE_OK ){
-    u64 nByte;                    /* Size of PMA in bytes */
+    u64 nByte = 0;                 /* Size of PMA in bytes */
     rc = vdbePmaReadVarint(pReadr, &nByte);
     pReadr->iEof = pReadr->iReadOff + nByte;
     *pnByte += nByte;