Update B2MML-TestSpecification.xsd

ERDi, MESA: complexType name = "TestSpecificationType" #24
CHANGE BACK To MASTER:  element name = "PhysicalSample" TO element name = "PhysicalSampleRequired".  
Even though Physical Sample aligns with updated Part 2, PhysicalSample Required is more explicit to the boolean defined values of "Yes" or "No".   Charlie Gifford will submit 95 committee comment to align with B2MML.

Schema/B2MML-TestSpecification.xsd

@@ -146,7 +146,7 @@ of test specifications.
                                                         minOccurs = "0"/>
       <xsd:element name = "RecurrenceTimeInterval"	type = "DurationType"
                                                         minOccurs = "0"/>
-      <xsd:element name = "PhysicalSample"		type = "IndicatorType"
+      <xsd:element name = "PhysicalSampleRequired"	type = "IndicatorType"
                                                         minOccurs = "0"/>
       <xsd:element name = "TestSpecificationChild"      type = "TestSpecificationType" 
                                                         minOccurs = "0" maxOccurs = "unbounded"/>