changelog.tcl: get optional argument for number of commits.
changelog.tcl: get optional argument for number of commits.

oranagra/redis,neomantra/redis,antirez/redis,PKRoma/redis,yossigo/redis,pmem/redis,soveran/redis,PKRoma/redis,soveran/redis,oranagra/redis,nnog/redis,pmem/redis,antirez/redis,ofirluzon/redis,spinlock/redis,charsyam/redis,antirez/redis,ofirluzon/redis,soveran/redis,charsyam/redis,nnog/redis,antirez/redis,charsyam/redis,charsyam/redis,nnog/redis,pmem/redis,neomantra/redis,pmem/redis,yossigo/redis,oranagra/redis,ofirluzon/redis,soloestoy/redis,ctripcorp/redis,yossigo/redis,soloestoy/redis,ctripcorp/redis,soloestoy/redis,nnog/redis,spinlock/redis,ctripcorp/redis,PKRoma/redis,yossigo/redis,yossigo/redis,PKRoma/redis,PKRoma/redis,spinlock/redis,soloestoy/redis,ofirluzon/redis,neomantra/redis,neomantra/redis,ofirluzon/redis,oranagra/redis,soloestoy/redis,oranagra/redis,spinlock/redis,charsyam/redis,soveran/redis,neomantra/redis,ctripcorp/redis