nsis: always use the regsvr32.exe from the system

We should not use whatever is in the PATH. Especially as the current directory
is set the a temporary directory during uninstallation.

(cherry picked from commit d13608f8)
Signed-off-by: Steve Lhomme <robux4@ycbcr.xyz>

extras/package/win32/NSIS/vlc.win32.nsi.in

@@ -416,7 +416,7 @@ ${MementoSection} "$(Name_Section04)" SEC04
   !insertmacro InstallFile axvlc.dll
   !insertmacro CloseUninstallLog
 @HAVE_WIN64_FALSE@ RegDLL "$INSTDIR\axvlc.dll"
-@HAVE_WIN64_TRUE@  ExecWait 'regsvr32.exe /s "$INSTDIR\axvlc.dll"'
+@HAVE_WIN64_TRUE@  ExecWait '"$SYSDIR\regsvr32.exe" /s "$INSTDIR\axvlc.dll"'
 ${MementoSectionEnd}
 !endif
 SectionGroupEnd
@@ -836,7 +836,7 @@ Section "un.$(Name_Section91)" SEC91
 
   ;remove activex plugin
 @HAVE_WIN64_FALSE@ UnRegDLL "$INSTDIR\axvlc.dll"
-@HAVE_WIN64_TRUE@  ExecWait 'regsvr32.exe /s /u "$INSTDIR\axvlc.dll"'
+@HAVE_WIN64_TRUE@  ExecWait '"$SYSDIR\regsvr32.exe" /s /u "$INSTDIR\axvlc.dll"'
   Delete /REBOOTOK "$INSTDIR\axvlc.dll"
 
   ;remove mozilla plugin