Improve svn-rev to search for pattern at line beginning.

	* gcc-git-customization.sh: Search for the pattern
	at line beginning only.

contrib/ChangeLog

+2020-04-03  Martin Liska  <mliska@suse.cz>
+
+	* gcc-git-customization.sh: Search for the pattern
+	at line beginning only.
+
 2020-01-24  Richard Earnshaw  <rearnsha@arm.com>
 
 	* gcc-git-customization.sh: Use users/<pfx> for the personal remote

contrib/gcc-git-customization.sh

@@ -18,7 +18,7 @@ ask () {
 }
 
 # Add a git command to find the git commit equivalent to legacy SVN revision NNN
-git config alias.svn-rev '!f() { rev=$1; shift; git log --all --grep="From-SVN: r\\?$rev\\b" "${@}"; } ; f'
+git config alias.svn-rev '!f() { rev=$1; shift; git log --all --grep="^From-SVN: r\\?$rev\\b" "${@}"; } ; f'
 
 # Add git commands to convert git commit to monotonically increasing revision number
 # and vice versa