make tracing jdbc flexible

[coveralls]

Pull Request Test Coverage Report for Build 93

• 44 of 70 (62.86%) changed or added relevant lines in 7 files are covered.
• 4 unchanged lines in 4 files lost coverage.
• Overall coverage increased (+2.2%) to 25.678%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/io/opentracing/contrib/jdbc/TracingCallableStatement.java	0	2	0.0%
src/main/java/io/opentracing/contrib/jdbc/TracingPreparedStatement.java	4	6	66.67%
src/main/java/io/opentracing/contrib/jdbc/JdbcTracingUtils.java	8	11	72.73%
src/main/java/io/opentracing/contrib/jdbc/TracingConnection.java	4	9	44.44%
src/main/java/io/opentracing/contrib/jdbc/ConnectionInfo.java	19	25	76.0%
src/main/java/io/opentracing/contrib/jdbc/TracingStatement.java	7	15	46.67%
<!--	Total:	44	70	62.86%	-->

Files with Coverage Reduction	New Missed Lines	%
src/main/java/io/opentracing/contrib/jdbc/TracingCallableStatement.java	1	0.0%
src/main/java/io/opentracing/contrib/jdbc/TracingPreparedStatement.java	1	15.38%
src/main/java/io/opentracing/contrib/jdbc/TracingStatement.java	1	26.52%
src/main/java/io/opentracing/contrib/jdbc/TracingConnection.java	1	25.88%
<!--	Total:	4		-->

Totals
Change from base Build 91:	2.2%
Covered Lines:	161
Relevant Lines:	627

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💛 - Coveralls