Fix compiler warnings

[jkandasa]

[INFO] Compiling 29 source files to /home/travis/build/Hawkular-QE/hawkular-java-client/target/classes
[WARNING] Cannot find annotation method 'value()' in type 'com.wordnik.swagger.annotations.ApiModelProperty': class file for com.wordnik.swagger.annotations.ApiModelProperty not found
[WARNING] Cannot find annotation method 'allowableValues()' in type 'com.wordnik.swagger.annotations.ApiModelProperty'
[WARNING] Cannot find annotation method 'value()' in type 'com.wordnik.swagger.annotations.ApiModelProperty'
[WARNING] Cannot find annotation method 'allowableValues()' in type 'com.wordnik.swagger.annotations.ApiModelProperty'
[WARNING] Cannot find annotation method 'value()' in type 'com.wordnik.swagger.annotations.ApiModelProperty'
[WARNING] Cannot find annotation method 'allowableValues()' in type 'com.wordnik.swagger.annotations.ApiModelProperty'
[WARNING] /home/travis/build/Hawkular-QE/hawkular-java-client/src/main/java/org/hawkular/client/metrics/model/Counter.java:[63,46] toStringHelper(java.lang.Object) in com.google.common.base.Objects has been deprecated
[WARNING] /home/travis/build/Hawkular-QE/hawkular-java-client/src/main/java/org/hawkular/client/metrics/model/CounterDataPoint.java:[89,46] toStringHelper(java.lang.Object) in com.google.common.base.Objects has been deprecated
[WARNING] /home/travis/build/Hawkular-QE/hawkular-java-client/src/main/java/org/hawkular/client/metrics/model/GaugeDataPoint.java:[89,46] toStringHelper(java.lang.String) in com.google.common.base.Objects has been deprecated
[WARNING] /home/travis/build/Hawkular-QE/hawkular-java-client/src/main/java/org/hawkular/client/metrics/model/AvailabilityDataPoint.java:[89,46] toStringHelper(java.lang.Object) in com.google.common.base.Objects has been deprecated
[WARNING] /home/travis/build/Hawkular-QE/hawkular-java-client/src/main/java/org/hawkular/client/metrics/model/Gauge.java:[64,46] toStringHelper(java.lang.Object) in com.google.common.base.Objects has been deprecated