fix bug when has complex expression on sharding column

[maxiaoguang64]

fix 1045

[coveralls]

Pull Request Test Coverage Report for Build 4959

• 25 of 31 (80.65%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 63.951%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sharding-core/src/main/java/io/shardingsphere/core/parsing/parser/clause/WhereClauseParser.java	23	29	79.31%

Files with Coverage Reduction	New Missed Lines	%
sharding-core/src/main/java/io/shardingsphere/core/parsing/parser/clause/InsertDuplicateKeyUpdateClauseParser.java	2	86.96%

Totals
Change from base Build 4958:	-0.003%
Covered Lines:	7944
Relevant Lines:	12422

---

💛 - Coveralls