quick fix for multi primary columns
quick fix for multi primary columns

by moving the call to `firstPrimaryColumn` under the condition `isManyToMany` wecan enable working inserts with multi primary columns for simple relations.

typeorm/typeorm,typeorm/typeorm,wpensar/ionic-orm,cserron/typeorm,BradyLiles/ionic-orm,Luke265/typeorm,typeorm/typeorm,wpensar/ionic-orm,gintsgints/typeorm,Luke265/typeorm,BradyLiles/ionic-orm,wpensar/ionic-orm,gintsgints/typeorm,ReaxDev/typeorm,ReaxDev/typeorm,cserron/typeorm