zdtm: fix awk script for Ubuntu

mawk doesn't handle '\<...\>'

Ubuntu:
$ awk -W version
mawk 1.3.3 Nov 1996, Copyright (C) Michael D. Brennan
$ ldd /bin/ps
	linux-vdso.so.1 =>  (0x00007fffb290a000)
$ ldd /bin/ps  | awk '/\<linux-vdso\.so\>/ { print $1 }'
$ ldd /bin/ps  | awk '/linux-vdso\.so/ { print $1 }'
linux-vdso.so.1

Fedora:
$ ldd /bin/ps
	linux-vdso.so.1 =>  (0x00007fff61fcb000)
$ ldd /bin/ps  | awk '/\<linux-vdso\.so\>/ { print $1 }'
linux-vdso.so.1
$ awk --version
GNU Awk 4.1.1, API: 1.1
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -436,9 +436,9 @@ construct_root()
 
 	local libs=$(ldd $test_path $ps_path | awk '
 		!/^[ \t]/ { next }
-		/\<linux-vdso\.so\>/ { next }
-		/\<linux-gate\.so\>/ { next }
-		/\<not a dynamic executable$/ { next }
+		/linux-vdso\.so/ { next }
+		/linux-gate\.so/ { next }
+		/not a dynamic executable$/ { next }
 		$2 ~ /^=>$/ { print $3; next }
 		{ print $1 }
 	')