glib-mkenums.in: fix @ENUMPREFIX@ with /*< underscore_name=... >*/
glib-mkenums.in: fix @ENUMPREFIX@ with /*< underscore_name=... >*/

For enums defined with an underscore_name override, @ENUMPREFIX@
would include a trailing "_". Fix.

https://bugzilla.gnome.org/show_bug.cgi?id=661797

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