Fix #824 : no corpus in init, but trim_rule in init (#1186)
Fix #824 : no corpus in init, but trim_rule in init (#1186)

* no corpus in init, but trim_rule in init

logged warning that trim_rule is being ignored for separate model initialization and vocabulary building

* log warning only when trim_rule is specified

summanlp/gensim,piskvorky/gensim,markroxor/gensim,piskvorky/gensim,ELind77/gensim,mattilyra/gensim,loisaidasam/gensim,laic/gensim,loisaidasam/gensim,robotcator/gensim,ELind77/gensim,jaksmid/gensim,mattilyra/gensim,dsquareindia/gensim,gojomo/gensim,markroxor/gensim,ELind77/gensim,robotcator/gensim,gojomo/gensim,quole/gensim,laic/gensim,jaksmid/gensim,gojomo/gensim,dsquareindia/gensim,RaRe-Technologies/gensim,robotcator/gensim,quole/gensim,macks22/gensim,jaksmid/gensim,quole/gensim,summanlp/gensim,Kreiswolke/gensim,piskvorky/gensim,loisaidasam/gensim,macks22/gensim,Kreiswolke/gensim,dsquareindia/gensim,RaRe-Technologies/gensim,Kreiswolke/gensim,bhargavvader/gensim,laic/gensim,mattilyra/gensim,bhargavvader/gensim,summanlp/gensim,macks22/gensim,gojomo/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim,bhargavvader/gensim,markroxor/gensim