Skip query if there is no any property key in schema

[javeme]

Change-Id: I23376791b3ffe54cf76413bf8d330694dbda2df8

[codecov]

Codecov Report

Merging #951 into master will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master     #951      +/-   ##
============================================
- Coverage     71.79%   71.79%   -0.01%     
  Complexity     4676     4676              
============================================
  Files           298      298              
  Lines         22377    22383       +6     
  Branches       3176     3178       +2     
============================================
+ Hits          16065    16069       +4     
+ Misses         4733     4732       -1     
- Partials       1579     1582       +3     

Impacted Files	Coverage Δ	Complexity Δ
...n/java/com/baidu/hugegraph/structure/HugeEdge.java	72.88% <0.00%> (-1.26%)	75.00 <0.00> (ø)
...java/com/baidu/hugegraph/structure/HugeVertex.java	78.05% <0.00%> (-1.01%)	78.00 <0.00> (ø)
...a/com/baidu/hugegraph/backend/query/Condition.java	79.67% <0.00%> (-0.41%)	31.00% <0.00%> (ø%)
...du/hugegraph/backend/tx/GraphIndexTransaction.java	79.58% <0.00%> (+0.12%)	186.00% <0.00%> (ø%)
...om/baidu/hugegraph/api/filter/ExceptionFilter.java	66.66% <0.00%> (+4.30%)	0.00% <0.00%> (ø%)

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