GHashTable: Small optimization of remove-all
GHashTable: Small optimization of remove-all

Don't enter the loop if we are not going to notify anyway.
Pointed out in bug 646013.

tchakabam/glib,tamaskenez/glib,djdeath/glib,pstglia/external-bluetooth-glib,ieei/glib,Distrotech/glib,darren-clark/android_platform_external_bluetooth_glib,01org/android-bluez-glib,01org/android-bluez-glib,mzabaluev/glib,justinkb/aosp-bluez.glib,cention-sany/glib,tchakabam/glib,Distrotech/glib,01org/android-bluez-glib,johne53/MB3Glib,gale320/glib,01org/android-bluez-glib,krichter722/glib,justinkb/aosp-bluez.glib,mzabaluev/glib,gale320/glib,bluez-android/glib,darren-clark/android_platform_external_bluetooth_glib,zsx/glib,endlessm/glib,djdeath/glib,krichter722/glib,cention-sany/glib,pstglia/platform-external-bluetooth-glib,justinkb/aosp-bluez.glib,cention-sany/glib,antono/glib,zsx/glib,iConsole/Console-OS_external_bluetooth_glib,gale320/glib,djdeath/glib,lukasz-skalski/glib,bluez-android/glib,bluez-android/glib,zsx/glib,iConsole/Console-OS_external_bluetooth_glib,krichter722/glib,pstglia/external-bluetooth-glib,lukasz-skalski/glib,endlessm/glib,mzabaluev/glib,lukasz-skalski/glib,mzabaluev/glib,antono/glib,justinkb/aosp-bluez.glib,iConsole/Console-OS_external_bluetooth_glib,01org/android-bluez-glib,justinkb/aosp-bluez.glib,johne53/MB3Glib,johne53/MB3Glib,gale320/glib,tchakabam/glib,cosimoc/glib,endlessm/glib,zsx/glib,antono/glib,tamaskenez/glib,iConsole/Console-OS_external_bluetooth_glib,MathieuDuponchelle/glib,darren-clark/android_platform_external_bluetooth_glib,cosimoc/glib,pstglia/platform-external-bluetooth-glib,MathieuDuponchelle/glib,darren-clark/android_platform_external_bluetooth_glib,endlessm/glib,tamaskenez/glib,johne53/MB3Glib,Distrotech/glib,mzabaluev/glib,pstglia/external-bluetooth-glib,tchakabam/glib,ieei/glib,pstglia/external-bluetooth-glib,johne53/MB3Glib,pstglia/platform-external-bluetooth-glib,tchakabam/glib,djdeath/glib,lukasz-skalski/glib,tamaskenez/glib,tamaskenez/glib,bluez-android/glib,MathieuDuponchelle/glib,darren-clark/android_platform_external_bluetooth_glib,MathieuDuponchelle/glib,djdeath/glib,ieei/glib,antono/glib,krichter722/glib,pstglia/platform-external-bluetooth-glib,ieei/glib,pstglia/platform-external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,krichter722/glib,lukasz-skalski/glib,MathieuDuponchelle/glib,johne53/MB3Glib,ieei/glib,cention-sany/glib,endlessm/glib,gale320/glib,cosimoc/glib,cosimoc/glib,bluez-android/glib,cention-sany/glib,pstglia/external-bluetooth-glib,cosimoc/glib,Distrotech/glib,Distrotech/glib