tools/memory-model: Use "grep -E" instead of "egrep"

The latest version of grep claims the egrep is now obsolete so the build
now contains warnings that look like:
egrep: warning: egrep is obsolescent; using grep -E
fix this up by moving the related file to use "grep -E" instead.

sed -i "s/egrep/grep -E/g" `grep egrep -rwl tools/memory-model`

Here are the steps to install the latest grep:

wget http://ftp.gnu.org/gnu/grep/grep-3.8.tar.gz
tar xf grep-3.8.tar.gz
cd grep-3.8 && ./configure && make
sudo make install
export PATH=/usr/local/bin:$PATH

Signed-off-by: Tiezhu Yang <[e-mail]>
Reviewed-by: Akira Yokosawa <[e-mail]>
Signed-off-by: Paul E. McKenney <[e-mail]>

tools/memory-model/scripts/checkghlitmus.sh

···
 # Create a list of the specified litmus tests previously run.
 ( cd $LKMM_DESTDIR; find litmus -name "*.litmus${hwfnseg}.out" -print ) |
 	sed -e "s/${hwfnseg}"'\.out$//' |
-	xargs -r egrep -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' |
+	xargs -r grep -E -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' |
 	xargs -r grep -L "^P${LKMM_PROCS}"> $T/list-C-already
 
 # Create a list of C-language litmus tests with "Result:" commands and
 # no more than the specified number of processes.
 find litmus -name '*.litmus' -print | mselect7 -arch C > $T/list-C
-xargs < $T/list-C -r egrep -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' > $T/list-C-result
+xargs < $T/list-C -r grep -E -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' > $T/list-C-result
 xargs < $T/list-C-result -r grep -L "^P${LKMM_PROCS}" > $T/list-C-result-short
 
 # Form list of tests without corresponding .out files