conf: Fix parsing python style triple quotes

An incorrect check broke matching the closing set of quotes. Update
tests to cover this case for XM config files.

src/util/conf.c

@@ -400,8 +400,9 @@ virConfParseString(virConfParserCtxtPtr ctxt)
         ctxt->cur += 3;
         base = ctxt->cur;
 
+        /* Find the ending triple quotes */
         while ((ctxt->cur + 2 < ctxt->end) &&
-               (STRPREFIX(ctxt->cur, "\"\"\""))) {
+               !(STRPREFIX(ctxt->cur, "\"\"\""))) {
             if (CUR == '\n')
                 ctxt->line++;
             NEXT;

tests/xmconfigdata/test-escape-paths.cfg

@@ -19,7 +19,7 @@ vnc = 1
 vncunused = 1
 vnclisten = "127.0.0.1"
 vncpasswd = "123poi"
-disk = [ "phy:/dev/HostVG/XenGuest2,hda,w", "file:/root/boot.iso&test,hdc:cdrom,r" ]
+disk = [ "phy:/dev/HostVG/XenGuest2,hda,w", "file:/root/boot.iso&test,hdc:cdrom,r", """phy:/dev/HostVG/XenGuest'",hdb,w""" ]
 vif = [ "mac=00:16:3e:66:92:9c,bridge=xenbr1,script=vif-bridge,model=e1000,type=ioemu" ]
 parallel = "none"
 serial = "none"

tests/xmconfigdata/test-escape-paths.xml

@@ -31,6 +31,11 @@
       <target dev='hdc' bus='ide'/>
       <readonly/>
     </disk>
+    <disk type='block' device='disk'>
+      <driver name='phy'/>
+      <source dev='/dev/HostVG/XenGuest&apos;&quot;'/>
+      <target dev='hdb' bus='ide'/>
+    </disk>
     <interface type='bridge'>
       <mac address='00:16:3e:66:92:9c'/>
       <source bridge='xenbr1'/>