Rename mysql module file.

diff --git a/org.glite.lbjp-common.db/src/db.c b/org.glite.lbjp-common.db/src/db-mysql.c
similarity index 100%
rename from org.glite.lbjp-common.db/src/db.c
rename to org.glite.lbjp-common.db/src/db-mysql.c