pgsql: Recognize ERROR_SHARING_VIOLATION (translate to EACCES), increase

Log Message:
-----------
Recognize ERROR_SHARING_VIOLATION (translate to EACCES), increase log
level for unrecognized win32 error codes to LOG, and make messages
conform to style guide.  Per old suggestion from Qingqing Zhou, which
seems to have gotten lost in the shuffle.

Modified Files:
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    pgsql/src/backend/port/win32:
        error.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/port/win32/error.c.diff?r1=1.4&r2=1.5)