tests: unify qemu binary paths for all qemu related tests

Our test data used a lot of different qemu binary paths and some
of them were based on downstream systems.

Note that there is one file where I had to add "accel=kvm" because
the qemuargv2xml code parses "/usr/bin/kvm" as virt type="kvm".

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

tests/domainschemadata/backing-chains.xml

@@ -13,7 +13,7 @@
   <on_reboot>restart</on_reboot>
   <on_crash>destroy</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu</emulator>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
     <disk type='network' device='disk'>
       <driver name='qemu' type='qcow2'/>
       <source protocol='gluster' name='Volume2/Image'>

tests/domainschemadata/default-cache-mode.xml

@@ -13,7 +13,7 @@
   <on_reboot>restart</on_reboot>
   <on_crash>destroy</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu</emulator>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
     <disk type='file' device='disk'>
       <driver name='qemu' type='raw' cache='default'/>
       <source file='/var/lib/libvirt/images/QEMUGuest1'/>

tests/domainschemadata/domain-bios-nvram-empty.xml

@@ -19,7 +19,7 @@
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu</emulator>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
     <disk type='block' device='disk'>
       <source dev='/dev/HostVG/QEMUGuest1'/>
       <target dev='hda' bus='ide'/>

tests/domainschemadata/maxMemory.xml

@@ -14,6 +14,6 @@
   <on_reboot>restart</on_reboot>
   <on_crash>destroy</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu</emulator>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
   </devices>
 </domain>

tests/domainschemadata/qemu-simple-description-title.xml

@@ -22,6 +22,6 @@
   <on_reboot>restart</on_reboot>
   <on_crash>restart</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu-kvm</emulator>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
   </devices>
 </domain>

tests/domainschemadata/timers.xml

@@ -16,7 +16,7 @@
   <on_reboot>restart</on_reboot>
   <on_crash>destroy</on_crash>
   <devices>
-    <emulator>/usr/bin/qemu</emulator>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
     <disk type='block' device='disk'>
       <source dev='/dev/HostVG/QEMUGuest1'/>
       <target dev='hda' bus='ide'/>