[python] Fix 9P muxing deadlock.
[python] Fix 9P muxing deadlock.

rvedam/wmii,sigmavirus24/wmii,jerluc/wmii,Sirikid/wmii,sigmavirus24/wmii,jerluc/wmii,rvedam/wmii,darkfeline/wmii,wingyplus/wmii,jerluc/wmii,Sirikid/wmii,Sirikid/wmii,Sirikid/wmii,Sirikid/wmii,wingyplus/wmii,jerluc/wmii,rvedam/wmii,rvedam/wmii,wingyplus/wmii,sigmavirus24/wmii,darkfeline/wmii,sigmavirus24/wmii,darkfeline/wmii,wingyplus/wmii,darkfeline/wmii,sigmavirus24/wmii,rvedam/wmii,darkfeline/wmii,jerluc/wmii,wingyplus/wmii